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Dr. Joseph A. Wright Dr. Jamie N. T. Peck Dr. Stephen P. Cottrell Dr. Aušra Jablonskytė Dr. Vasily S. Oganesyan Prof. Christopher J. Pickett Dr. Upali A. Jayasooriya 《Angewandte Chemie (International ed. in English)》2016,55(47):14580-14583
The chemistry of metal hydrides is implicated in a range of catalytic processes at metal centers. Gaining insight into the formation of such sites by protonation and/or electronation is therefore of significant value in fully exploiting the potential of such systems. Here, we show that the muonium radical (Mu.), used as a low isotopic mass analogue of hydrogen, can be exploited to probe the early stages of hydride formation at metal centers. Mu. undergoes the same chemical reactions as H. and can be directly observed due to its short lifetime (in the microseconds) and unique breakdown signature. By implanting Mu. into three models of the [FeFe]‐hydrogenase active site we have been able to detect key muoniated intermediates of direct relevance to the hydride chemistry of these systems. 相似文献
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W. Czapliński A. Kravtsov A. Mikhailov N. Popov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,3(3):223-227
Nuclear fusion reactions in hydrogen-lithium muonic molecules, (where h=p,d,t) are considered and fusion rates from rotational states J=0 of the molecules are presented. Results obtained depend on the isotopic composition of the molecules and range between
and . The upper limit for fusion rates from rotational states J=0 of hydrogen-helium muonic molecules, and , equal , is also found.
Received: 4 December 1997 / Revised: 30 April 1998 / Accepted: 7 May 1998 相似文献
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Two species of Mu centers with extremely small hyperfine parameters have been observed in single crystalline ZnO below 40
K. Both Mu centers have an axial symmetric hyperfine structure along with the [0001] axis, indicating that they are located
at ABO,∥ and BC∥ sites. It is inferred from their small ionization energy (≃6 meV and 50 meV) and hyperfine parameters (∼10−4 times the vacuum value) that these centers behave as shallow donors, strongly suggesting that hydrogen is one of the primary
origins of n type conductivity in as-grown ZnO.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
45.
Klaus P. Jungmann 《Hyperfine Interactions》2001,138(1-4):463-473
New intense proton accelerators with above GeV energies and MW beam power, such as they are discussed in connection with neutrino
factories, appear to be excellently suited for feeding bright muon sources for low-energy muon science. Muon rates with several
orders of magnitude increased flux compared to present facilities will become available. This will allow higher precision
in experiments which were statistics limited so far such as searches for rare decays, muonium spectroscopy, muon capture,
muon catalyzed fusion, muon decay studies and measurements muon moments and parameters. Novel and most important experiments
will become possible. For example a permanent electric dipole moment (edmμ) of a muon could be searched with by far unprecedented accuracy and with a physics potential well beyond the possibilities
of present electron, neutron and nuclear edm searches. Investigations of short lived radioactive nuclei using muonic atom
spectroscopy would become feasible.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
46.
S.V. Romanov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,2(3):217-230
In recent experiments performed at the Paul Scherrer Institute (PSI) measurements were made of the yield of the two-photon transition of the fully-ionized muonic boron formed and quenched in a gaseous mixture of diborane B2H6 and helium. In the present work this yield is calculated for an idealized case of a very low diborane density when the main
2
s state decay modes competing with the two-photon transition are due to the electron transfer from helium to the μ-ion. As
the rate of this transfer depends strongly on the relative velocity, a treatment is needed of the whole kinetics of processes
occurring with the μ-ion in helium. Accordingly, within the optical model with a complex potential constructed before we calculate
cross-sections of the elastic scattering and electron transfer. Then the time evolution of the μ-ion energy is considered
and, finally, the yield is calculated. It proves that at helium pressures Torr this yield may be written in the form: ,where the factor C is greater than unity and increases rapidly with the initial energy E0 which the μ-ion has after its formation in the diborane molecule. Thus measurement of the pressure dependence of allows E0 to be estimated. The results obtained make it possible to suggest a similar parametrization of the PSI data.
Received: 21 October 1997 / Revised: 16 January 1998 / Accepted: 2 March 1998 相似文献
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Rate constants for the reactions of muonium (Mu) (the ultralight isotope of the hydrogen atom) with H2O2 in H2O and D2O2 in D2O have been determined at various temperatures and pH (pD) values. The data are consistent with the three reactions: , , and the equivalent for the deuterated entities. A significant positive H/D isotope effect was found for the undissociated peroxide, while for the anions the effect was negligible or slightly in the opposite direction. In addition, for concentrated solutions of peroxide a study of the muon spin polarization as a function of applied transverse magnetic field yielded results consistent with the rate constants determined from the direct decay measurements, and indicated that the reaction products are diamagnetic, most likely MuH and MuOH, i. e., no muoniated radical products are formed. These results are potentially relevant for management of the radiolysis products in nuclear industry. 相似文献