# Last edited on 2019-04-24 01:38:06 by stolfilocal
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* Abstract: The spontaneous decay of chemically bound radioactive atoms affords a route to ions of well-defined structure and charge location, free of counterions. The nuclear nature of the ionization process makes it insensitive to environmental effects, so that exactly the same charged species can be generated, and its reactivity investigated, in widely varying media, from low-pressure gases to liquids and solids. Techniques based on nuclear decay are used in studies of the production of otherwise inaccessible species, the structural characterization of free ions, and the comparative evaluation of their reactivity in different environments, in particular, gas phase and solution.<ref name=fcac1990>
<ref name=akul1976>G. P. Akulov (1976): "Ion-molecular reactions initiated by β-decay of tritium in tritiated compounds" ("Ionn-molekulyarnye reaktsii, initsiirovannye β-raspadom tritiya v tritirovannykh soedineniyakh"). ''Uspekhi Khimii'' (USSR), volume 45, issue 2, pages 1970-1999. (No DOI). <!-- Note: Survey of Cacace's radioactive decay method. Discusses reactions of {{chem2|[^{3}HeT](+)}} with methane, ethane, propane, butane and also with cycloalkanes from C3 to C6. Surveys literature before 1974.--></ref>
<ref name=atti1977>Marina Attina, Fulvio Cacace, Giovanna Ciranni, and Pierluigi Giacomello (1977): "Aromatic substitution in the gas phase. Ambident behavior of phenol toward t-C4H9+ cations". ''Journal of the American Chemical Society'', volume 99, issue 15, pages 5022–5026. {{doi|10.1021/ja00457a022}}.</ref>
<ref name=atti1979>Marina Attinà , Fulvio Cacace, Giovanna Ciranni, and Pierluigi Giacomello (1979): "Gas-phase reaction of free isopropyl ions with phenol and anisole". ''Journal of the Chemical Society, Perkin Transactions 2'', issue 7, pages 891-895. {{doi|10.1039/P29790000891}}</ref>
<ref name=atti1980>Marina Attina, Fulvio Cacace, and Pierluigi Giacomello (1980): "Aromatic substitution in the gas phase. A comparative study of the alkylation of benzene and toluene with C3H7+ ions from the protonation of cyclopropane and propene". ''Journal of the American Chemical Society'', volume 102, issue 14, pages 4768–4772. {{doi|10.1021/ja00534a032}}</ref>
<ref name=atti1983>Marina Attina, and Fulvio Cacace (): "Aromatic substitution in the gas phase. Intramolecular selectivity of the reaction of aniline with charged electrophiles". ''Journal of the American Chemical Society'', volume 105, issue 5, pages 1122–1126. {{doi|10.1021/ja00343a009}}</ref>
<ref name=atti1985>Marina Attina, Fulvio Cacace, and Giulia De Petris (1085): "Intramolecular selectivity of the alkylation of substituted anilines by gaseous cations". ''Journal of the American Chemical Society'', volume 107, issue 6, pages 1556–1561. {{doi|10.1021/ja00292a017}}</ref>
<ref name=colo1984>H. Colosimo, M. Speranza, F. Cacace, G. Ciranni (1984): "Gas-phase reactions of free phenylium cations with C3H6 hydrocarbons", ''Tetrahedron'', volume 40, issue 23, pages 4873-4883. {{doi|10.1016/S0040-4020(01)91321-3}}</ref>
<ref name=fcac1963>Fulvio Cacace (1964): ''Proceedings of the 1963 Conference on the Methods for Preparing and Storing Marked Molecules'', Bruxelles, page 179. Euratom report EUR.1625.e.<!--Note: first publication of the decay method. Out of print and apparently unavailable online.--></ref>
<ref name=fcac1966>Fulvio Cacace, Giovanna Ciranni, and Angelo Guarino (1966): "A Tracer Study of the Reactions of Ionic Intermediates Formed by Nuclear Decay of Tritiated Molecules. I. Methane-t4". ''Journal of the American Chemical Society'', volume 88, issue 13, pages 2903–2907. {{doi|10.1021/ja00965a004}} <!--Note: Quotes that THe+ is produced in radiolysis of H3TC with 0.15% probability.--></ref>
<ref name=fcac1970>Fulvio Cacace (1970): "Gaseous Carbonium Ions from the Decay of Tritiated Molecules". ''Advances in Physical Organic Chemistry'', volume 8, pages 79-149. {{doi|10.1016/S0065-3160(08)60321-4}}</ref>
<ref name=fcac1973>Fulvio Cacace and Pierluigi Giacomello (1973): "Gas-phase reaction of tert-butyl ions with arenes. Remarkable selectivity of a gaseous, charged electrophile". ''Journal of the American Chemical Society'', volume 95, issue 18, pages 5851–5856. {{doi|10.1021/ja00799a002}}</ref>
<ref name=fcac1977aFulvio Cacace and Pierluigi Giacomello (1977): "Aromatic substitution in the liquid phase by bona fide free methyl cations. Alkylation of benzene and toluene". ''Journal of the American Chemical Society'', volume 99, issue 16, pages 5477–5478. {{doi|10.1021/ja00458a040)).</ref>
<ref name=fcac1978>Fulvio Cacace and Pierluigi Giacomello (1978): "Aromatic substitutions by [{{chem2|^{3}H3}}]methyl decay ions. A comparative study of the gas- and liquid-phase attack on benzene and toluene". ''Journal of the Chemical Society, Perkin Transactions 2'', issue 7, pages 652-658. {{doi|10.1039/P29780000652}}</ref>
<ref name=fcac1981>Fulvio Cacace, Giovanna Ciranni, and Pierluigi Giacomello (1981): "Aromatic substitution in the gas phase. Alkylation of arenes by gaseous C4H9+ cations". ''Journal of the American Chemical Society'', volume 103, issue 6, pages 1513–1516. {{doi|10.1021/ja00396a035}}</ref>
<ref name=fcac1982>Fulvio Cacace (1982): "On the formation of adduct ions in gas-phase aromatic substitution". ''Journal of the Chemical Society, Perkin Transactions 2'', issue 9, pages 1129-1132. {{doi|10.1039/P29820001129}}.</ref>
<ref name=fcac1982b>Fulvio Cacace, Giovanna Ciranni, and Pierluigi Giacomello (1982): "Alkylation of nitriles with gaseous carbenium ions. The Ritter reaction in the dilute gas state". ''Journal of the American Chemical Society'', volume 104, issue 8, pages 2258–2261. {{doi|10.1021/ja00372a025}}</ref>
<ref name=fcac1982c>Fulvio Cacace, Giovanna Ciranni and Pierluigi Giacomello (1982): "Aromatic substitution in the gas phase. Alkylation of arenes by C4H9+ ions from the protonation of C4 alkenes and cycloalkanes with gaseous Brønsted acids". ''Journal of the Chemical Society, Perkin Transactions 2'', issue 11, pages 1129-1132. {{doi|10.1039/P29820001129}}</ref>
<ref name=fcac1986>Fulvio Cacace, and Giovanna Ciranni (1986): "Temperature dependence of the substrate and positional selectivity of the aromatic substitution by gaseous tert-butyl cation". ''Journal of the American Chemical Society'', volume 108, issue 5, pages 887–890. {{doi|10.1021/ja00265a006}}</ref>
<ref name=fcac1990>Fulvio Cacace (1990): "Nuclear Decay Techniques in Ion Chemistry". ''Science'', volume 250, issue 4979, pages 392-399. {{doi|10.1126/science.250.4979.392}}. <!--Note: Short survey.--></ref>
<ref name=fcac1992>Fulvio Cacace, Maria Elisa Crestoni, and Simonetta Fornarini (1992): "Proton shifts in gaseous arenium ions and their role in the gas-phase aromatic substitution by free Me3C+ and Me3Si+ [tert-butyl and trimethylsilyl] cations". ''Journal of the American Chemical Society'', volume 114, issu 17, pages 6776–6784. {{doi|10.1021/ja00043a024}}</ref>
<ref name=fcac1993>Fulvio Cacace, Maria Elisa Crestoni, Simonetta Fornarini, and Dietmar Kuck (1993): "Interannular proton transfer in thermal arenium ions from the gas-phase alkylation of 1,2-diphenylethane". ''Journal of the American Chemical Society'', volume 115, issue 3, pages 1024–1031. {{doi|10.1021/ja00056a029}}</ref>
<ref name=giac1976>Pierluigi Giacomello and Fulvio Cacace (1976): "Gas-phase alkylation of xylenes by tert-butyl(1+) ions". ''Journal of the American Chemical Society'', volume 98, issue 7, pages 1823–1828.{{doi|10.1021/ja00423a029}}</ref>
<ref name=sper1993>Maurizio Speranza (1993): "Tritium for generation of carbocations". ''Chemical Reviews'', volume 93, issue 8, pages 2933–2980. {{doi|10.1021/cr00024a010}}.<!--Note: extensive review of the chemistry of {{chem2|[^{3}HeT](+)}} produced by decay of tritiated organic molecules. Part of a more general review of Cacace's radiolytic method for generating carbon radicals and C+ cations.--></ref>
<ref name=lloy1968>Roger Vaughan Lloyd, Frank A. Magnotta, and David Eldon Wood (1968): "Electron paramagnetic resonance study of free-radical reactions initiated by radioactive decay in solid naphthalene-1-t". ''Journal of the American Chemical Society'', volume 90, issue 25, pages 7142–7144. {{doi|10.1021/ja01027a057}}</ref>
<ref name=lloy1970>V. Lloyd and D. E. Wood (1970): "EPR Studies of 1-Naphthyl and 2-Naphthyl Radicals Produced by Tritium Decay". ''Journal of Chemical Physics'', volume 52, pages 2153-2154. {{doi|10.1063/1.167326952}}}</ref>
* Resistivity of solid naphthalene is \rho_0 \exp(0.73 ev/kT). Drops from ~ 10^14 ohm cm to ~4 x 10^10 on melting.
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<ref name=sper1993>Maurizio Speranza (1993): "Tritium for generation of carbocations". ''Chemical Reviews'', volume 93, issue 8, pages 2933–2980. {{doi|10.1021/cr00024a010}}.<!--Note: extensive review of the chemistry of {{chem2|[^{3}HeT](+)}} produced by decay of tritiated organic molecules. Part of a more general review of Cacace's radiolytic method for generating carbon radicals and C+ cations.--></ref>
* Radiolysis of H-T (or T-T) yields yields a stable ion {{chem2|[^{3}He^{1}H](+)}} (or {{chem2|[^{3}HeT](+)}}) in the ground state with 90-95% probability, because the energy of 3He-H bond in {{chem2|[^{3}He^{1}H](+)}} is 1.85eV, so that the recoil energy needed to split is ~1.7 eV, but the recoil energy available is only 1.6 eV.<ref name=sper1993/>
* Radiolysis of R-T (where R is rooted at a carbon atom) yields R-3He+, but that breaks apart to R+ and 3He because the energy of 3He-C bond is ~1 eV, so that the recoil energy needed to break the bond is ~1.1 eV (for a multi-carbon R), and the decay provides 1.6 eV of recoil energy. This is a reliable way to create R+ cations; about 80% of the R+ produced resists further fragmentation, at least in the first 10-100 \mu s. The R+ cation is suddenly formed in the same solvation state and carbon bond geometry as the parent R-T (e.g., tetrahedral for H3C+, instead of planar), and usually reacts/relaxes before an organized solvent shell can be formed. <ref name=sper1993/>
* The ions {{chem2|[^{3}HeT](+)}}, formed from decay of {{chem2|T2}}, can be used as extremely powerful protonating agents in gas-phese ion chemistry.<ref name=sper1993/>
* The decay of CT4 (tetra-tritiated methane) produces T3C+ that can be used to selctively tritiate other organic compounds.<ref name=sper1993/>
* The {{chem2|[^{3}HeT](+)}} reacts with methane to produce (tritiated) methonium [CH4T+]* in an excited state. The methonium then may decay to CH3T, CH4, or H3C+. Or it may react with methane to produce [CH4T++].<ref name=sper1993/>
[4] Cacace, F. Proceedings of the Conference on the Methods for Preparing and Storing Marked Molecules 1963;Sarchis,J.,Ed.;Euratom Report EUR.1625.e :Bruxelles,1964;p719. ,1964; p719.
[5] Cacace, F. Adv. Phys. Org. Chem. 1970, 8, 79.
[6] Cacace, F.; Giacomello,P.J. Chem. Soc., Perkin Trans. 21978, 652.
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<ref name=akul1976>G. P. Akulov (1976): "Ion-molecular reactions initiated by β-decay of tritium in tritiated compounds" ("Ionn-molekulyarnye reaktsii, initsiirovannye β-raspadom tritiya v tritirovannykh soedineniyakh"). ''Uspekhi Khimii'' (USSR), volume 45, issue 2, pages 1970-1999. (No DOI). <!-- Note: Survey of Cacace's radioactive decay method. Discusses reactions of {{chem2|[^{3}HeT](+)}} with methane, ethane, propane, butane and also with cycloalkanes from C3 to C6. Surveys literature before 1974.--></ref>
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Liquid-phase reactions of free methyl cations from the decay of methane-t4. Alternative alkylation sites in halobenzenes
Pierluigi Giacomello
J. Am. Chem. Soc., 1979, 101, issue 15, pages 4276–4281
. {{doi|10.1021/ja00509a039}}
Publication Date: July 1979
ACS Legacy Archive
a)Cacace,F.,Schuller,M.,J.LabelledCompd.1975,11,313.
(b)Cacace,F.;Ciranni,G.;Schuller,M.,J.Am.Chem.Soc.1975,97,4747.
(6)Cacace,F.Adv.Phys.Org.Chem.1970,8,79.
(7)Cacace,F.;Glacomello,P.J.Am.Chem.Soc.1977,99,5477.
(8)Cacace,F.;Glacomello,P.J.Chem.Soc.,PerkinTrans.21978,652.
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# YES <ref name=schw1955>H. M. Schwartz (1955): "Excitation of Molecules in the Beta Decay of a Constituent Atom". ''Journal of Chemical Physics'', volume 23, pages 400-401. {{doi|10.1063/1.1741982}}.</ref>
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# YES * In 1955, H. Schwarz predicted theoretically that the decay of {{chem2|T2}} should produce bound {{chem2|[^{3}HeT](+)}} with high probability.<ref name-schw1955/>
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<ref name=rait1974>R. Raitz Von Frentz, K. Luchner, H. Micklitz, V. Wittwer (1974): "Observation of vibrational transitions in {{chem2|[^{3}He^{3}H](+)}} after β-decay in the tritium molecule". ''Physics Letters A'', volume 47, issue 4, pages 301-302. {{doi|10.1016/0375-9601(74)90175-3}}</ref>
The helium hydride ion was detected spectroscopically by R. Von Frentz and others in 1974. Specifically, they detected the infrared radiation with wavelength 4.69 μm, due to decay of the vibrational excited state ν=1 of {{chem2|^{3}HeT(+)}} ({{chem2|[^{3}He\s^{3}H](+)}}), generated from decay of {{chem2|T2}}, at 25 K. The emission disappeared when the parent {{chem2|T2}} was cooled below 20 K.<ref name=rait1974>
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<ref name=fack1985>O. Fackler, B. Jeziorski, W. Kołos, H. J. Monkhorst, and K. Szalewicz (1985): "Accurate Theoretical β-Decay Energy Spectrum of the Tritium Molecule and Its Neutrino Mass Dependence". ''Physical Reviews Letters'', volume 55, issue 13, pages 1388-1391.{{doi|10.1103/PhysRevLett.55.1388}}</ref>
* Abstract: The β-decay energy spectrum which results from the decay of one of the nuclei in the {{chem2|T2}} molecule has been computed. An accurate, explicitly correlated basis set was used to describe electronic states of both the parent and the daughter molecules, and effects of nuclear motion have been taken into account. All the channels which meaningfully affect the spectrum have been incorporated, including resonance and scattering channels. The spectra are presented for several neutrino masses. It is shown that the molecular effects are crucial for accurately determining the neutrino mass from a tritium β-decay experiment.<ref name=fack1985/>
* In 1980, V Lyubimov at the [[ITEP]] laboratory in Moscow claimed to have detected a significant rest mass (30 ± 12) eV for the [[neutrino]], by analyzing the energy spectrum of the β decay of tritium. It was known that some of the energy released by that decay would be diverted to the excitation of the decay products, including that ion; and this phenomenon was a source of error in that experiment. That motivated numerous efforts to precisely compute the expected energy states of that ion in order to reduce the uncertainty of those measurements.<ref name=fack1985/>
* The electronic states of the {{chem2|[^{3}HeT](+)}} ion and their distribution as generated by β decay of {{chem2|T2}} were computed by O. Fackler and others in 1985. They found that the ion would be in the ground state with 57.4% probability, and in electronically excited but still bound states with 27.8% probability (85.2% total), and in states in the ionization continuum with 14.8% probability.<ref name=fack1985/>
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# YES
# YES
# YES <ref name=bain1933>Kenneth T. Bainbridge (1933): "Comparison of the Masses of H<sup>2</sup> and Helium". ''Physical Reviews'', volume 44, issue 1, page 57. {{doi|10.1103/PhysRev.44.57}}</ref>
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# YES * In 1933, K. Bainbridge compared the masses of {{chem2|[^{4}He^{1}H](+)}} and {{chem2|[^{2}H2^{1}H](+)}} (dideuterium hidrogen ion) in order to obtain an accurate measure of the atomic mass of deuterium. Both have 3 protons, 2 neutrons, 2 electrons. He also compared {{chem2|[^{4}He^{2}H](+)}} (helium deuteride ion) with {{chem2|[^{2}H3](+)}} (trideuterium ion).<ref name=bain1933/>
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# YES <ref name=beac1936>J. Y. Beach (1936): "Quantumâ€Mechanical Treatment of Helium Hydride Moleculeâ€Ion HeH<sup>+</sup>". ''Journal of Chemical Physics'', volume 4, issue 6, pages 353-357. {{doi|10.1063/1.1749857}} Note: First satisfactory theoretical computation of bond energy (2.02eV) and length (157 pm) and fundamental vibration wavelength (3.57 \mu m).</ref>
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# YES * In 1936, J. Y. Beach made the first theoretical computation of the expected energy (2.02eV), length (83 pm), and fundamental vibration wavelength (3.57 \mu m) of the He-H bond.<ref name=beac1936/>
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# YES * Abstract: Helium hydride moleculeâ€ion has been treated by the variation method, including ionic and polarization terms in the variation function and varying the effective nuclear charge. The equilibrium internuclear distance is found to be 1.57a0. Fitting a parabola to the lower part of the best potential energy curve leads to a value of 0.43 megadyne/cm for the force constant and a value of 2800 cm—1 for the fundamental vibration frequency. The minimum energy obtained for the system is —5.844WH, which, when subtracted from the best value for the energy of the helium atom using the same type of variation function, gives a value for the dissociation energy of 2.02 ev. The doubly charged ion, HeH++, is found to be unstable.<ref name=beac1936/>.
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# YES <ref name=evet1956>Arthur A. Evett (1956): "Ground State of the Heliumâ€Hydride Ion". ''Journal of Chemical Physics'', volume 24, issue 1, pages 150-152. {{doi|10.1063/1.1700818}}<!--Computed minimum binding energy 1.68 eV, length 76 pm, and vibration radiation wavelength 2.8 \mu m.--></ref>
# YES
# YES * In 1956, A. Evett computed minimum binding energy 1.68 eV, length 76 pm, and vibration radiation wavelength 2.8 \mu m for the He-H bond.<ref name=evet1956/>
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# YES * Abstract: The variational method developed by James and Coolidge was applied to the ground state of (He H)+, extending the earlier work of Coulson and Duncanson and of Toh. Several terms not considered previously in the power series expansion of the wave function in elliptic coordinates were found to be very effective in increasing the binding energy. Calculations with a 20â€term wave function gave an equilibrium internuclear separation of 1.432 a0 and a fundamental frequency of 3600 cm−1. A 23â€term wave function established 1.68 ev as the lower limit for the corrected dissociation energy.<ref name=evet1956/>
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* 1991 neutrino mass
# NO
# NO Physical Review Letters
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# NO Limit on ν¯e mass from observation of the β decay of molecular tritium
# NO R. G. H. Robertson, T. J. Bowles, G. J. Stephenson, Jr., D. L. Wark, J. F. Wilkerson, and D. A. Knapp
# NO Phys. Rev. Lett. 67, 957 – Published 19 August 1991
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# NO We report the most sensitive direct upper limit set on the mass mν of the electron antineutrino. Our measurements of the shape of the β decay spectrum of free molecular tritium yield, under the assumption of no new physics other than that of mass, a central value for m2ν of -147±68±41 eV2, which corresponds to an upper limit of 9.3 eV (95% confidence level) on mν. The result is in clear disagreement with a reported value of 26(5) eV.
# NO
# NO Received 6 May 1991
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# NO. {{doi|10.1103/PhysRevLett.67.957}}
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# NO Mentions "internal and translational degrees of freedom of the {{chem2|[^{3}HeT](+)}} ion", citing "J.S.Cohen(privatecommunication)"
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* 1995 neutrino mass. Accounts for {{chem2|[^{3}HeT](+)}} excitation.
# NO Physical Review Letters
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# NO Anomalous Structure in the Beta Decay of Gaseous Molecular Tritium
# NO Wolfgang Stoeffl and Daniel J. Decman
# NO Phys. Rev. Lett. 75, 3237 – Published 30 October 1995
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# NO We have made high statistics measurements of tritium beta decay to set a limit on the mass of the electron antineutrino. The measurements used a windowless gaseous source of molecular tritium and a high resolution toroidal field magnetic spectrometer. We calibrate the system using conversion electrons from the decay of 83mKr. The best fit value for the neutrino mass squared is significantly negative. An anomalous structure in the beta decay spectrum in the last 55 eV closest to the end point causes this result.
# NO
# NO Received 13 January 1994
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# NO. {{doi|10.1103/PhysRevLett.75.3237}}
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# NO The beta decay of molecular tritium populates many levels of the daughter He-T+ molecule. These levels and their population in the beta decay of {{chem2|T2}} have been extensively calculated (see [7] and references therein). The calculations show that 57.4% of the decays lead to the ground electronic state, 27.8% to bound excited states, and 14.8% to states in the ionization continuum
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# NO [7] O.Fackler, B.Jeziorski, W.Kolos, H.J.Monkhorst, and K.Szalewicz, Phys.Rev.Lett. 55,1388 (1985).
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# NO [8] P.Froelich, B.Jeziorski, W.Kolos, H.J.Monkhorst, A.Saenz, and K.Szalewicz, Phys.Rev.Lett. 71,2871 (1993)
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* 1987 Neutrino mass, no mention of {{chem2|[^{3}HeT](+)}}
# NO Physical Review Letters
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# NO Limit on ¯νe Mass from Free-Molecular-Tritium Beta Decay
# NO J. F. Wilkerson, T. J. Bowles, J. C. Browne, M. P. Maley, R. G. H. Robertson, J. S. Cohen, R. L. Martin, D. A. Knapp, and J. A. Helffrich
# NO Phys. Rev. Lett. 58, 2023 – Published 18 May 1987
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# NO The beta spectrum of free molecular tritium has been measured in order to search for a finite electron-antineutrino mass. The final-state effects in molecular tritium are accurately known and the data thus yield an essentially model-independent upper limit of 27 eV on the νe mass at the 95% confidence level.
# NO
# NO Received 17 November 1986
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# NO. {{doi|10.1103/PhysRevLett.58.2023}}
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# NO ©1987 American Physical Society
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# NO No explicit mention
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# YES <ref name=bern1982>P. Bernath and T. Amano (1982): "Detection of the Infrared Fundamental Band of HeH<sup>+</sup>". ''Physical Review Letters'', volume 48, issue 1, pages 20-22. {{doi|10.1103/PhysRevLett.48.20}} <!--Note: first infrared detection--></ref>
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# YES * Abstract: Nine vibration-rotation transitions of the fundamental band of HeH<sup>+</sup> have been observed in absorption by using a tunable, infrared, difference-frequency laser source. The molecular constants for the v=0 and v=1 levels of the X1Σ+ state have been determined and they agree very will with those derived from the ab initio calculation of Bishop and Cheung.<ref name=bern1982/>
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# YES * The first spectral detection by D.E.Tolliver, G.A.Kyrala,andW.H.Wing,Phys.Rev.Lett.43,1719(1979).ThispaperreferencesmuchofthepreviousexperimentalworkonHeH<sup>+</sup>.
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# YES <ref name=toll1979>David E. Tolliver, George A. Kyrala, and William H. Wing (1979): "Observation of the Infrared Spectrum of the Helium-Hydride Molecular Ion {{chem2|[^{4}HeH](+)}}". ''Physical Review Letters'', volume 43, issue 23, pages 1719-1722. {{doi|10.1103/PhysRevLett.43.1719}}<!--Note: first vibrational-rotational spectrum--></ref>
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# YES * Abstract: We have made the first observation of the vibrational-rotational spectrum of the electronic ground state of the helium-hydride molecular ion {{chem2|[^{4}He^{1}H](+)}}. The Doppler-tuned ion-beam laser-spectroscopic technique was used. The frequencies of five transitions between 1700 and 1900 cm−1 have been measured to ± 0.002 cm−1 (±1 pagesm). The experimental values deviate from current theory by typically 0.2 cm−1, and are two orders of magnitude more precise than the theoretical values.
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# <ref name=tung2012>Wei-Cheng Tung, Michele Pavanello, and Ludwik Adamowicz (2012): "Accurate potential energy curves for HeH<sup>+</sup> isotopologues ". ''Journal of Chemical Physics'', volume 137, issue 16, pages 164305. {{doi|10.1063/1.4759077}}<!--Note: precise computations for {{chem2|[^{4}He^{1}H](+)}}, {{chem2|[^{4}He^{2}H](+)}}, {{chem2|[^{3}He^{1}H](+)}}, and {{chem2|[^{3}He^{2}H](+)}}.--></ref>
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# * In 2012 W. Tung and others published more precise computations for {{chem2|[^{4}He^{1}H](+)}}, {{chem2|[^{4}He^{2}H](+)}}, {{chem2|[^{3}He^{1}H](+)}}, and {{chem2|[^{3}He^{2}H](+)}}. The bond length for {{chem2|[^{4}He^{1}H](+)}} was 77 pm.
#
# * Abstract: New accurate ground-state potential energy curves (PEC) for the {{chem2|[^{4}He^{1}H](+)}}, {{chem2|[^{4}He^{2}H](+)}}, {{chem2|[^{3}He^{1}H](+)}}, and {{chem2|[^{3}He^{2}H](+)}} isotopologues are calculated with 600 explicitly correlated Gaussian (ECG) functions with shifted centers in the range between R = 0.35 a0 and 145 a0. The calculations include the adiabatic corrections (AC). The absolute accuracy of all Born-Oppenheimer (BO) PEC points is better than 0.0018 cm−1 and it is better than 0.0005 cm−1 for the ACs. With respect to the very recent BO PEC calculations performed by Pachucki with 20 000 generalized Heitler-London explicitly correlated functions [K. Pachucki, Phys. Rev. A 85, 042511 (2012)], the present energy calculated at R = 1.46 a0 (a point near the BO equilibrium distance) lies above by only 0.0012 cm−1. Using Pachucki's BO energy at the equilibrium distance of R = 1.463 283 a0, and the adiabatic corrections calculated in this work for the {{chem2|[^{4}He^{1}H](+)}}, {{chem2|[^{4}He^{2}H](+)}}, {{chem2|[^{3}He^{1}H](+)}}, and {{chem2|[^{3}He^{2}H](+)}} isotopologues, the following values are obtained for their PEC depths: 16 448.99893 cm−1, 16 456.86246 cm−1, 16 451.50635 cm−1, and 16 459.36988 cm−1, respectively. We also calculate the rovibrational (rovib) frequencies for the four isotopologues using the BO PEC of Pachucki augmented with the present ACs. The improvements over the BO+AC PEC of Bishop and Cheung (BC) [J. Mol. Spectrosc. 75, 462 (1979)] are 1.522 cm−1 at R = 4.5 a0 and 0.322 cm−1 at R = ∞. To partially account for the nonadiabatic effects in the rovib calculations an effective reduced-mass approach is used. With that, the present {{chem2|[^{4}He^{1}H](+)}} rovibrational transitions are considerably improved over the BC transitions as compared with the experimental values. Now the rovibrational transitions near the dissociation limit are as well reproduced by the present calculations as the lower transitions. For example, for the {{chem2|[^{4}He^{2}H](+)}} transitions corresponding to the ν = 13-9 hot bands the results are off from the experimental values by less than 0.023 cm−1. This confirms high accuracy of the present PECs at larger internuclear separations.
#
# * The first direct infrared spectrum of {{chem2|[^{4}He^{1}H](+)}} by Bernath and T. Amano,Phys. Rev. Lett.48, 20 (1982).
#
# * First accurate computation for {{chem2|[^{4}He^{1}H](+)}} by L. Wolniewicz,J. Chem. Phys.43, 1087 (1965).
#
#
----------------------------------------------------------------------
# YES
# YES <ref name=pach2012>Krzysztof Pachucki and Jacek Komasa (2012): "", ''Journal of Chemical Physics'', volume 137, issue 20, article 204314. {{doi|10.1063/1.4768169}} <!--Note: accurate computation for {{chem2|[^{4}HeH](+)}}.--></ref>
# YES
# YES * Helium hydride ion {{chem2|[^{4}He^{1}H](+)}} and dihydrogen ion H2+ are first molecules formed in big bang model.<ref name=pach2012/>
# YES
# YES * Abstract: Dissociation energy (D0) of rovibrational levels of {{chem2|[^{4}He^{1}H](+)}} has been predicted theoretically to the accuracy of the order of 0.01 cm−1. The calculations take into account adiabatic and nonadiabatic corrections as well as relativistic and quantum electrodynamics effects. For the ground rovibrational level D0 = 14 874.215(10) cm−1 and it differs by several tens of the inverse centimeter from previous theoretical estimations. For a collection of about 50 transition energies measured between dipole connected levels the difference between theory and experiment is of the order of hundredths of cm−1 or less.<ref name=pach2012/>
# YES
----------------------------------------------------------------------
<ref name=snel1957>Arthur H. Snell, Frances Pleasonton, H. E. Leming (1957): "Molecular dissociation following radioactive decay: Tritium hydride". ''Journal of Inorganic and Nuclear Chemistry'', volume 5, issue 2, pages 112-117. {{doi|10.1016/0022-1902(57)80051-7}}</ref>
Elsevier
* Abstract: When radioactive decay takes place in the TH molecule, the resulting (He3H)+ ion shows a strong tendency to remain bound. When dissociation does take place, the electrons most commonly divide one with each nucleus, rather than both going either with the He3 fragment or with the H fragment. These conclusions are derived from a magnetic analysis of the ions produced as the result of TH decay, the observed relative intensities being as follows: (He3H)+, 93·2 ± 1·9 per cent; (He3)+, 5·1 ± 0·3 per cent; H+, 1·55 ± 0·16 per cent; (He3)++, 0·14 ± 0·01 per cent. The molecule loses an electron in fewer than 1·7 per cent of the decay events.<ref name=snel1957/>
* In 1957, A. Snell experimentally found that the main ions produced by {{chem2|T2}} decay comprised the bound {{chem2|[^{3}HeT](+)}} ion (93.2%), 3He+ (5.1%), T+ (1.55%), and 3He++ (0.14%)
* On the other hand, (HeH)+ is known to be stable; it has been observed in mass spectrometry, (2-3) and several computations (4-8) have been made of its binding energy, the most recent of these leading to values slightly under 2 eV. Accordingly, there exists also an expectation that some of the (He^33H)+ ions may remain bound.
(2) T. R. HOGNESS and E. G. LUNN Phys. Rev. 26, 44 (1925).
(3) K. T. BAINBRIDGE Phys. Rev. 44, 57 (1933).
(4) j. y. BEACH J. chem. Phys. 4, 353 (1936).
(5) C. k. COULSON and W. E. DUNCANSON Proc. roy. Soc. A 165, 90 (1938).
(6) S. TOH Proc. phys.-math. Soc. Japan 22, 119 (1940).
(7) A. A. EVETT d. chem. Phys. 24, 150 (1956).
(8) A. C. HURLEY Proc, phys. Soc. A 69, 868 (1956).
----------------------------------------------------------------------
<ref name=stoh1940>Sôroku Toh (1940): "Quantum-Mechanical Treatment of Helium-Hydride Molecule Ion HeH<sup>+</sup>". ''Proceedings of the Physico-Mathematical Society of Japan'', 3rd Series, volume 22, issue 2, pages 119-126. {{doi|10.11429/ppmsj1919.22.2_119}}.<!--Theoretically computed 1.28 eV for dissociation energy, fundamental vibration 3400 waves/cm, 71 pm for bond length.--></ref>
----------------------------------------------------------------------
Physics Letters B
Volume 173, Issue 4, 19 June 1986, Pages 485-489
open access
Physics Letters B
An upper limit for the mass of
from tritium β-decay
Author links open overlay panelM.Fritschi12E.Holzschuh12W.Kündig12J.W.Petersen121R.E.Pixley12H.Stüssi12
https://doi.org/10.1016/0370-2693(86)90420-X
Get rights and content
Abstract
The endpoint region of the tritium β-spectrum has been measured with 27 eV resolution, using a magnetic spectrometer. The tritium activity was implanted into a thin layer of carbon. The
mass determined is consistent with zero with an upper limit of 18 eV, which includes instrumental and statistical uncertainties due to the energy loss in the source and the final electronic states.
Implanted {{chem2|T2}} in carbon film, assumed that C-T bonds formed. No explicit mention of {{chem2|[^{3}HeT](+)}}
----------------------------------------------------------------------
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Molecular effects in investigations of tritium molecule β decay endpoint experiments
Natasha Doss, Jonathan Tennyson, Alejandro Saenz, and Svante Jonsell
Phys. Rev. C 73, 025502 – Published 17 February 2006
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PDFHTMLExport Citation Vol. 73, Iss. 2 — February 2006
Abstract
The final state distribution of the first six electronic states of {{chem2|[^{3}HeT](+)}}, {{chem2|[^{3}He^{2}H](+)}} and {{chem2|[^{3}He^{1}H](+)}} resulting from the β decay of {{chem2|T2}}, DT, and HT are calculated, to satisfy the higher-resolution requirements and increased sensitivity of the future tritium neutrino mass experiments. The sensitivity of the initial temperature, ortho-para ratio, and isotopic composition of the source is considered. Estimates of the error in the value of the neutrino mass deduced from fitting, due to uncertainties in the temperature, the ortho-para ratio of {{chem2|T2}}, and the percentage of DT molecules in the source are presented.
Theoretical calculations.
the Rydberg states and the electronic continuum of {{chem2|[^{3}HeT](+)}} start at 40 eV below the endpoint [15],
These excited states are essentially dissociative. The n=2, 4, and 5 states dissociate to He+ & T, and the n=3 and 6 states dissociate to He & T+.
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Molecular effects in tritium β decay: Transitions to the discrete electronic states of the HeT+ molecule
Wl/odzimierz Kol/os, Bogumil/ Jeziorski, Krzysztof Szalewicz, and Hendrik J. Monkhorst
Phys. Rev. A 31, 551 – Published 1 February 1985
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Abstract
The energies and wave functions for the lowest six electronic 1Σ+ states of the HeT+ molecule have been obtained for 0.6≤R≤4.0 bohr. The overlap integrals between these wave functions and those for the ground state of the {{chem2|T2}} molecule have been calculated. The results show that the probability of {{chem2|T2}} decaying into HeT+ discrete electronic states amounts to 0.852, with the lowest six states accounting for 0.8422.
Received 18 September 1984
Mentions DT but does not have any info on it.
. {{doi|10.1103/PhysRevA.31.551}}
----------------------------------------------------------------------
The European Physical Journal C - Particles and Fields
April 2005, Volume 40, Issue 4, pages 447–468 | Cite as
Final results from phase II of the Mainz neutrino mass searchin tritium ð›½
decay
Authors
Authors and affiliations
Ch KrausB. BornscheinL. BornscheinJ. BonnB. FlattA. KovalikB. OstrickE. W. OttenEmail authorJ. P. SchallTh ThümmlerCh Weinheimer
Ch Kraus
1
B. Bornschein
1
L. Bornschein
1
J. Bonn
1
B. Flatt
1
A. Kovalik
1
B. Ostrick
1
E. W. Otten
1Email author
J. P. Schall
1
Th Thümmler
1
Ch Weinheimer
12
1.Institut für Physik der Johannes Gutenberg-Universität MainzMainzGermany
2.Helmholtz-Institut für Strahlen und KernphysikUniversität BonnBonnGermany
experimental physics
4 Shares 503 Downloads 385 Citations
Abstract.
This paper reports on the improved Mainz experiment on tritium ð›½
spectroscopy which yields a 10 times higher signal to background ratio than before. The main experimental effects and systematic uncertainties have been investigated in side experiments, and possible error sources have been eliminated. Extensive data taking took place in the years 1997 to 2001. A residual analysis of the data sets yields for the square of the electron antineutrino mass the final result of ð‘š2(ðœˆð‘’)=(−0.6±2.2stat±2.1syst) eV2/c4. We derive an upper limit of ð‘š(ðœˆð‘’)≤2.3 eV/c2 at 95% confidence level for the mass itself.
Cite this article as:
Kraus, C., Bornschein, B., Bornschein, L. et al. Eur. Phys. J. C (2005) 40: 447. https://doi.org/10.1140/epjc/s2005-02139-7
DOI https://doi.org/10.1140/epjc/s2005-02139-7
Uses D2 for spectrometer calibration, but no DT decay.
----------------------------------------------------------------------
Outline
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References
Elsevier
Physics Letters B
Volume 287, Issue 4, 13 August 1992, Pages 381-388
open access
Physics Letters B
Measurement of the electron neutrino mass from tritium β-decay
Author links open overlay panelE.HolzschuhM.FritschiW.Kündig
https://doi.org/10.1016/0370-2693(92)91000-Y
Measurements of the tritium ß-spectrum are reported. Thin sources consisting of a monolayer of tritiated hydrocarbon molecules were used. No indication of a nonzero mass mν of the electron antineutrino was found. The result is m2ν=−24 ± 48 ± 61 eV2 (1σ). An upper limit mν < 11 eV (95% confidence level) is derived.
The tritium sources were produced by the sponta- neous formation of a self-assembhng monolayer The pnnclple of the method is illustrated in fig 3 and has been described previously [6] First, tntlated molecules, consisting of a simple hydrocarbon chain with 18 C-atoms and a reactive SiCl3 endgroup are prepared (octadecyltrichlorosilane, OTS) The surface of the substrate consists of SiO2, treated such that it is densely covered by OH groups. A highly diluted solution (2 × 10 -3 molar) of OTS is prepared into which the substrate is dipped for a short time (5 min) The SiCl 3 groups of OTS react with the OH groups on the surface, forming Si-O bonds and HC1 is released into the solution The reactions come to an end when the surface is densely covered by a monolayer and looks then as indicated on the right of fig 3 Such monolayers have been studied extensively by Sagw et al and others [8]
No mention of the THe3+
----------------------------------------------------------------------
Half-Life of Molecular Tritium and the Axial-Vector Interaction in Tritium β Decay
B. Budick, Jiansheng Chen, and Hong Lin
Phys. Rev. Lett. 67, 2630 – Published 4 November 1991
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Abstract
The half-life of tritium has been measured by monitoring the decay of the x-ray bremsstrahlung emitted by gaseous mixtures of {{chem2|T2}} and Xe. The result, 12.31±0.03 yr, when combined with the end-point energy measured on the same sources, yields the product (GA/G′V)〈σ〉=2.098±0.003, where 〈σ〉 is the Gamow-Teller matrix element. Combined with a recent precise calculation of the matrix element, this value suggests that the renormalization of the axial-vector interaction can be entirely accounted for by nuclear effects in the triton. The deduced value of GA/G′V constrains the neutron lifetime to lie in the range of 897±3 s.
Received 8 May 1991
. {{doi|10.1103/PhysRevLett.67.2630}}
Mentions {{chem2|[^{3}HeT](+)}} but not much info.
----------------------------------------------------------------------
Physical Review A
covering atomic, molecular, and optical physics and quantum information
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Molecular effects in tritium β decay. IV. Effect of crystal excitations on neutrino mass determination
W. Kol/os, B. Jeziorski, J. Rychlewski, K. Szalewicz, H. J. Monkhorst, and O. Fackler
Phys. Rev. A 37, 2297 – Published 1 April 1988
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We have computed the excitation probabilities of the {{chem2|T2}} molecules in the crystal surrounding the β-decaying tritium. The influence of this effect on the neutrino mass determination has been studied. For a neutrino mass of the order of a few eV the effect has been shown to be very important. Its importance decreases, however, with increasing neutrino mass. In addition we consider the influence of the high-energy portion (E>164 eV) of the probability distribution on the neutrino mass.
Received 13 October 1987
. {{doi|10.1103/PhysRevA.37.2297}}
Theoretical. Computes what happens in solid {{chem2|T2}} when it changes into {{chem2|[^{3}HeT](+)}}
----------------------------------------------------------------------
<ref name=cant1956>Murray Cantwell (1956): "Molecular Excitation in Beta Decay". ''Physical Reviews'', volume 101, issue 6, pages 1747-1756.{{doi|10.1103/PhysRev.101.1747}}.<!--Note: predicts theoretically that the ground state vibrational spectrum of {{chem2|[^{3}HeT](+)}} should be observable in the
the light emitted by {{chem2|T2}}. Says that if {{chem2|[^{3}HeT](+)}} lines are too far into the infrared, {{chem2|[^{3}He^{2}H](+)}} and {{chem2|[^{3}He^{1}H](+)}} may be easier to detect--></ref>
* Abstract: The theory of molecular excitation in beta decay is developed for the general case of a polyatomic molecule. Calculations of the daughter molecule vibrational excitation are carried through for diatomic molecules, and the results are presented graphically. Finally, the formation of the (He3H3)+ molecule ion in the decay of one nucleus of a tritium molecule is studied in detail. It is concluded that the (He3H3)+ ground electronic state vibrational spectrum should be observable in the light spontaneously emitted by tritium. For example, neglecting nonradiative transitions, one expects approximately 1014 photons per second to be radiated at wave number ≅2.35×103 cm−1 by every gram of tritium in the 1→0 vibrational transition.<ref name=cant1956/>
Received 6 April 1955
. {{doi|}}
Theoretical. Predicts that the formation of {{chem2|[^{3}HeT](+)}} should be observable in the
spectrum of the light emitted by {{chem2|T2}}.
{{chem2|T2}} --> THe+, <ref name=cant1956/>
{{chem2|[^{4}He^{1}H](+)}} electronically almost identical to {{chem2|[^{3}HeT](+)}}<ref name=cant1956/>
{{chem2|[^{3}He^{2}H](+)}} and {{chem2|[^{3}He^{1}H](+)}} vibrational spectra lie nearer to the visible
so may be easier to detect.<ref name=cant1956/>
----------------------------------------------------------------------
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Reports on Progress in Physics
Neutrino mass limit from tritium β decay
E W Otten1,3 and C Weinheimer2
Published 29 July 2008 • 2008 IOP Publishing Ltd
Reports on Progress in Physics, Volume 71, Number 8
IOP PUBLISHINGREPORTS ONPROGRESS INPHYSICSRep. Prog. Phys.71(2008) 086201 (36pp)doi:10.1088/0034-4885/71/8/086201
he first electronicexcitation of the (3HeT)+ion at 24 eV
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Neutrino Mass from the Beta Spectrum in the Decay of Tritium
S. Boris, A. Golutvin, L. Laptin, V. Lubimov, V. Nagovizin, V. Nozik, E. Novikov, V. Soloshenko, I. Tihomirov, E. Tretjakov, and N. Myasoedov
Phys. Rev. Lett. 58, 2019 – Published 18 May 1987; Erratum Phys. Rev. Lett. 61, 245 (1988)
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The data from the spectrum measurement of the tritium decay in a valine molecule carried out in a wide energy range (3.4 keV) with the Institute of Theoretical and Experimental Physics spectrometer are analyzed. The combined analysis of both these data and the data of the previous cycle gives the neutrino mass 30.3+2−8 eV. The model-independent mass interval 17<Mν<40 eV is derived from the mass difference of the doublet 3H-3He.
Received 12 November 1986
. {{doi|10.1103/PhysRevLett.58.2019}}
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Journal of Physics B: Atomic and Molecular Physics
Electronic resonances of HeT+ resulting from the beta decay of the tritium molecule
P Froelich, K Szalewicz, B Jeziorski, W Kolos and H J Monkhorst
Journal of Physics B: Atomic and Molecular Physics, Volume 20, Number 23
Calculations for the three lowest resonant states of the molecular ion HeT+ are presented. These states are known to be produced with high probabilities in the beta decay of the {{chem2|T2}} molecule. Therefore, their positions and widths are needed for an accurate interpretation of the neutrino mass experiments employing {{chem2|T2}} molecules as a source of radiation. These quantities may also be useful in interpreting low-energy He++H scattering and far-ultraviolet spectroscopy of HeH<sup>+</sup>. The resonance positions and widths have been obtained using the method of analytic continuation of the real valued stabilisation graphs calculated with a basis set of explicitly correlated functions in elliptic coordinates. A discussion of the complex scaling method in these coordinates is given, and an appropriate stabilisation transformation pertinent to the use of elliptic coordinates is derived. As a test of the method, the lowest resonant states of the H2 molecule and Li+ ion have also been calculated, and the results agree very well with data in the literature obtained with much more laborious methods.
Theoretical
----------------------------------------------------------------------
Title:
Molecular effects in tritium beta decay. II - Rotation-vibration excitation, dissociation, and rotational predissociation in the decay of the {{chem2|T2}} and TH molecules
Authors:
Jeziorski, B.; Kolos, W.; Szalewicz, K.; Fackler, O.; Monkhorst, H. J.
Affiliation:
AA(Florida, University, Gainesville; Warszawa, Uniwersytet, Warsaw, Poland; Waterloo, University, Canada), AB(Florida, University, Gainesville; Warszawa, Uniwersytet, Warsaw, Poland), AC(Florida, University, Gainesville; Warszawa, Uniwersytet, Warsaw, Poland), AD(Rockefeller University, New York; California, University, Livermore), AE(Florida, University, Gainesville)
Publication:
Physical Review A - General Physics, 3rd Series (ISSN 0556-2791), vol. 32, Nov. 1985, p. 2573-2583. Research supported by the University of Florida. (PhRvA Homepage)
Publication Date:
11/1985
Category:
Nuclear and High-Energy Physics
Origin:
STI
NASA/STI Keywords:
Electron States, Molecular Excitation, Molecular Rotation, Radioactive Decay, Transition Probabilities, Tritium, Beta Particles, Gas Dissociation, Ground State, Neutrinos, Particle Mass, Vibrational Spectra
. {{doi| }}
10.1103/PhysRevA.32.2573
Bibliographic Code:
1985PhRvA..32.2573J
Abstract
Probabilities have been computed for transitions induced by a beta-decay process from the ground rovibronic state of the {{chem2|T2}} molecule to various bound rovibrational and scattering states connected with the first six 1Sigma(+) electronic states of the He-3T(+) ion. Analogous calculations were performed for the TH source, but only the ground electronic state of the daughter system was considered. For transitions from the {{chem2|T2}} source to the ground electronic state of the daughter ion, a probability equal to 0.4083 is associated with bound rovibrational states, while 0.1659 is associated with scattering states. The same values for the TH source are 0.5572 and 0.0136, respectively. It is shown that the use of a TH source is not advantageous in a neutrino-mass experiment. Numerical accuracies of these calculations have been checked by making extensive use of sum rules. The total error in the final result is discussed.
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Bound Electron Creation in the Decay of Tritium
P. M. Sherk
Phys. Rev. 75, 789 – Published 1 March 1949
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Abstract
The relative probabilities of K creation and beta-emission are calculated for both molecular and atomic tritium. This ratio is shown to be 0.0035 for the molecule and 0.0065 for the atom, assuming the maximum kinetic energy of the beta-rays to be 16.9 kev.
Received 19 November 1948
. {{doi|10.1103/PhysRev.75.789}}
There is a finite probability that decay of {{chem2|T2}} will produce a neutral THe molecule by capturing the beta.
It goes into the K shell of the molecule.
----------------------------------------------------------------------
Nuclear Physics A
Volume 719, 19 May 2003, Pages C153-C160
Nuclear Physics A
The search for the neutrino mass by direct method in the tritium beta-decay and perspectives of study it in the project KATRIN
Author links open overlay panelV.M.Lobasheva
https://doi.org/10.1016/S0375-9474(03)00985-0
The updated results of the search for neutrino mass in the tritium beta-decay on the Troitsk nu-mass and Neutrino Mainz set-ups are presented. Both groups give an upper limit for the neutrino mass at 95% mv < 2.05 eV/c2 in Troitsk and mv < 2.2 V/c2 in Mainz. Further improvement is limited both by statistic and systematic errors. In order to enter in the cosmologically important sub-electronvolt area the collaboration of groups from Karlsruhe Forschungszentrum, Mainz, Troitsk et al. proposed a new advanced project KATRIN. The status of the project is presented.
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Physica Scripta
On Some Atomic Effects in the Tritium β-Spectrum
Karl-Erik Bergkvist
Physica Scripta, Volume 4, Number 1-2
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Abstract
The present work forms part of a detailed investigation of the upper end-point region of the tritium β-spectrum, aiming at improved information on neutrino mass, neutrino degeneracy and on the ft-value of the tritium β-decay, the latter being of interest for judging the applicacability of PCAC for obtaining the modification of the axial-vector matrix element due to pion exchange. By the application of high-efficient β-spectroscopic methods a considerable improvement in basic accuracy of data has been achieved, making it necessary to inspect in a more detailed way than previously done how the interplay between a β-decaying nucleus and its atomic surrounding affects the observed β-spectrum. The β-decay of an atom leads to a distribution in atomic final states; the present work is essentially concerned with the various quantitative consequences of this circumstance for the case of the tritium decay. The distribution in atomic final states is found to imply a mean square energy spread as large as (27 eV)2 in the end-point energy of the spectrum from the tritium atom. This inherent spread in end-point energy is comparable in magnitude with the experimental resolution width now reached in the investigation of the tritium β-spectrum and has to be considered when interpreting the exprimental data with respect to limits on neutrino mass and neutrino degeneracy. The spread in end-point energy found will present a severe inherent difficulty in any effort to improve further the experimental information on these two entities. The distribution in atomic final states also affects the interpretation of the extrapolated end-point energy in terms of the H3-He3 nuclear mass difference and further is found to imply that the proper screening potential to be employed in the Fermi function differs by no less than 50% from the value conventionally assumed. An approximate treatment of the β-decay of the T-H molecule indicates that no drastic change in the atomic effects on the tritium spectrum should result when the tritium atom is not free but chemically bound in some more complex atomic surrounding. Some consequences of a minor residual ambiguity in the magnitude of the atomic effects in this case are commented on.
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Molecular effects in tritium β decay. III. Electronic resonances of the HeT+ ion and dependence of neutrino mass on the accuracy of the theoretical model
K. Szalewicz, O. Fackler, B. Jeziorski, W. Kol/os, and H. J. Monkhorst
Phys. Rev. A 35, 965 – Published 1 February 1987
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The theoretical aspects of the β-decay process in {{chem2|T2}} as they relate to neutrino-mass experiments are discussed. We present new results from stabilization method calculations for the resonance states of the daughter HeT+ ion. The probabilities for this system to be found in various final shake-off states after the {{chem2|T2}} decay have been calculated. The β-decay energy spectra are generated using probability distributions of various accuracies. It is shown that, if the actual neutrino mass were 30 eV, one would obtain masses of 6 and 25 eV using spectra of the bare tritium nucleus and the tritium atom, respectively, for analyzing the data. If the nuclear motion effects were neglected, the obtained mass would be 30 eV but the end-point energy would be shifted by 1.5 eV. For a 30-eV mass the accuracy of our calculations is much better than necessary: Substituting our data by those obtained with a very poor basis set changed the neutrino mass only by about 1 eV. For a 1-eV mass, however, the less accurate calculation would introduce a substantial error. In particular, including the effects of nuclear motion is important to correctly determine a 1-eV mass. The accuracy with which resonance states of the daughter ion are determined has practically no influence on the final result. We argue that most solid-state effects will lead to corrections small compared to the expected experimental errors.
Received 12 May 1986
. {{doi|10.1103/PhysRevA.35.965}}
Theoretical
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Improved Molecular Final-State Distribution of HeT+ for the β-Decay Process of {{chem2|T2}}
Alejandro Saenz, Svante Jonsell, and Piotr Froelich
Phys. Rev. Lett. 84, 242 – Published 10 January 2000
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Abstract
An improved theoretical final-state distribution of HeT+ (and HeH<sup>+</sup>) resulting from the β decay of molecular tritium {{chem2|T2}} (HT) is presented to accommodate the needs of increased accuracy in the analysis of ongoing and future tritium neutrino-mass experiments. The previously available theoretical spectrum has been improved in many respects, and adopted approximations have been validated.
Received 26 April 1999
. {{doi|10.1103/PhysRevLett.84.242}}
Theoretical
Table comparing THe+ and HHe+ (helium3)
Small but aparently significant differences
For the first energy 0.053 eV for T, 0.049 eV for H; but Prob for HHe+ is zero, 0.0069% for THe+.
Most likely state for HHe+ : level 15, 1.452 eV, Prob 9.5%
Most likely state for THe+ : level 16, 1.552 eV, Prob 6.9%
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Physics Letters B
Volume 460, Issues 1–2, 5 August 1999, Pages 219-226
open access
Physics Letters B
High precision measurement of the tritium β spectrum near its endpoint and upper limit on the neutrino mass
Author links open overlay panelCh.Weinheimer11B.Degenddag22A.BleileJ.BonnL.BornscheinO.Kazachenko33A.Kovalik44E.W.Otten
https://doi.org/10.1016/S0370-2693(99)00780-7
The Mainz neutrino mass experiment investigates the endpoint region of the tritium β decay spectrum to determine the mass of the electron antineutrino. By the recent upgrade the former problem of dewetting {{chem2|T2}} films has been solved and the signal-to-background-ratio was improved by a factor of 10. The latest measurement leads to , from which an upper limit of (95% C.L.) is derived. Some indication for the anomaly, reported by the Troitsk group, was found, but its postulated half year period is contradicted by our data.
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Home > The Journal of Chemical Physics > Volume 32, Issue 4 > 10.1063/1.1730880
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Full Published Online: 29 July 2004
Dissociation of C6H5T Following Beta Decay
J. Chem. Phys. 32, 1234 (1960); https://doi.org/10.1063/1.1730880
Thomas A. Carlson
Finds that in the dissociation of monotritiated benzene, 0.37% of the fragments
are either TH+ or {{chem2|[^{3}He^{1}H](+)}}. (mass/charge = 4)
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Journal of Inorganic and Nuclear Chemistry
Volume 10, Issues 1–2, April 1959, Pages 8-16
Journal of Inorganic and Nuclear Chemistry
Dissociation of TH and {{chem2|T2}} by β-decay☆
Author links open overlay panelS.Wexler
https://doi.org/10.1016/0022-1902(59)80180-9
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Abstract
The positively charged fragments resulting from β-decay in the diatomic molecules TH and {{chem2|T2}} were analysed by the techniques of mass spectrometry. The data on tritium hydride support the findings of Snellet al. (1) that the (HHe3)+ daughter usually remains bound in the nuclear transformations. The stability against dissociation of the ionized daughter molecules [(HHe3)+ and (THe3)+] was observed to depend slightly on the mass of the bonding partner. The results are discussed within the framework of the Franck-Condon principle.
For TH: {{chem2|[^{3}He^{1}H](+)}} 89.5%, 3He+ 8.3%, H+ 2.3%, (3He)++ ~0%
For TT: HeT+ 94.5%, T+ + 3He+ 5.5%
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<ref name=lyub1980>V. A. Lubimov, E. G. Novikov, V. Z. Nozik, E. F. Tretyakov, V. S. Kosik (1980): "An estimate of the ν<sub>e</sub> mass from the β-spectrum of tritium in the valine molecule", ''Physics Letters B'', volume 94, issue 2, pages 266-268. {{doi|10.1016/0370-2693(80)90873-4}}.<!--Found a mass between 14 and 46 eV. Negated by later experiments.--></ref>
* Abstract: The high energy part of the β-spectrum of tritium in the valine molecule (C5H11NO2) was measured with a high precision by a toroidal β-spectrometer. The results give evidence for a non-zero electron antineutrino mass.<ref name=lyub1980/>