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No abstract available

No abstract available

No abstract available

[en] In this communication a model of the hydrogen atom with all electromagnetic effects is presented and the process of the standard geometric quantization is tested by comparison with the previous results

[en] A new high precision measurement of the muonium hyperfine structure interval Δν and its Zeeman effect in the n = 1 ground state is being undertaken at LAMPF. Aiming for a precision of 50 ppb for the muon to proton magnetic ratio μ_μ/μ_p and of 10 ppb for Δν, the present experimental uncertainties can be reduced by a factor of about 5 using line-narrowing techniques. It is emphasized that still more precise measurements would be possible in the future with the realization of a more intense pulsed muon source

[en] Electron capture Β-decay at low temperatures is discussed. It is shown that the capture of s-electrons, from inner closed electronic shells in many-electron atoms and ions, is considerably altered by the hyperfine interaction. The capture rate can depend significantly on the hyperfine state of the decaying isotope. The total decay rate of a sample of a capture isotope will therefore depend on the populations of the hyperfine states and hence on temperature. The effect is shown to persist in the presence of a magnetic field. The effects should be observable experimentally in paramagnetic atoms or ions cooled to temperatures comparable to the hyperfine splitting. These conditions can be achieved using laser cooling in the gas phase or with conventional cryogenic techniques in solids. Potential applications in neutrino research and nuclear physics are described

[en] The aim of this contribution is to shed some light on the kind of information that can extracted from the analysis of the amplitude of the ENDOR (Electron Nuclear Double Resonance) signals of radicals in the solid state. It is shown how it is possible to study internal motions which are too fast or to slow to affects the EPR (Electron Paramagnetic Resonance) lineshapes, and to obtain the principal directions of hyper-fine tensors from the spectra in disordered matrices. The factors affecting the intensity of the signal are considered. The definition of ENDOR enhancement is given and the explicit expressions for it are derived for some simple cases. The applicability of the general theory to ENDOR in the solid state is discussed. The spin relaxation mechanisms in this state are briefly reviewed. The exchange between inequivalent protons causes some non-secular terms of the spin Hamiltonian to fluctuate, activate nuclear, electron or cross nuclear-electron relaxation paths. It is shown, by referring to some specific cases, that the enhancement is greatly affected by these mechanisms, for both very slow or very fast conformational motions. (author). 37 refs.; 9 figs.; 1 tab

No abstract available

[en] We present results of atom interferometry experiments in which spatial matter - wave interference is revealed by its selective destruction. A thermal potassium beam is transmitted through a velocity selective atom interferometer and detected. The interferometer is a sequence of three diffraction gratings. Interference fringes forming a Moire pattern with the third grating determine the transmission. The thermal beam produces a velocity average over different fringe Fourier components, each resonant in the interferometer at a different atomic velocity. AC modulated laser light passes through the interferometer, near the middle grating. Since imaging of the fluorescent light could be used to determine which slit an atom passes, the contribution to the fringe pattern by atoms at the laser's Doppler shifted wavelength is removed. That component is thus AC modulated and detected. This open-quotes atom interference filterclose quotes resolves the K³⁹ HFS