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961.
The electronic spectrum of an icosahedral quasicrystal with a central-atom decoration of the Amman-Mackay network is investigated
in the tight-binding approximation. The quasicrystal is described as a structural limit of the optimal cubic approximants
with increasing period. The electronic spectra for the first four optimal cubic approximants do not contain the hierarchical
gap structure which is typical for the Cantor set of the spectrum of a one-dimensional quasicrystal. At the same time, as
the order of the approximant increases, the spectrum becomes singular throughout the entire energy scale.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 8, 557–562 (25 April 1998)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
962.
We show that “top-down” mechanisms of ultrahigh-energy cosmic rays which involve heavy relic particle-like objects predict
a Galactic anisotropy of the highest-energy cosmic rays at the level of minimum ∼ 20%. This anisotropy is large enough to
be either observed or ruled out in the next generation of experiments.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 2, 99–103 (25 July 1998)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
963.
An expression for the probability of thermally activated tunneling ionization in an electric field in the presence of a magnetic
field is obtained. It is shown that the logarithm of the ionization probability is proportional to the squared electric field,
and the coefficient of proportionality decreases with increasing magnetic field.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 10, 763–767 (25 November 1998) 相似文献
964.
965.
On the basis of exactly solvable stationary models for the Schrödinger equation, we develop a procedure for solving the nonstationary Schödinger equation in an explicit analytic form. We investigate the formation of the nonadiabatic geometric phase during cyclic evolution of a quantum system. 相似文献
966.
Absolute total electron scattering cross sections for carbon dioxide have been measured at low electron energies using a photoelectron
source. The measurements have been carried out at 27 electron energies varying from 0.91–9.14 eV with an accuracy of ±3%.
The cross sections obtained in the present experiment have been compared with other measurements and theoretical computations. 相似文献
967.
Mass distributions of fragments in the low-energy fission of nuclei from 187Ir to 213At have been analysed. This analysis has shown that shell effects in symmetric-mode fragment mass yields from the fission of pre-actinide nuclei could be described if one assumes the existence of two strongly deformed neutron shells in the arising fragments with neutron numbers N1 ≈ 52 and N2 ≈ 68. A new method has been proposed for quantitatively describing the mass distributions of the symmetric fission mode for pre-actinides with A ≈ 180–220. 相似文献
968.
We present a variational treatment for the E × e pseudo Jahn-Teller system. Through canonical transformation the electron and phonon states are decoupled. An analytical form is obtained for the ground state energy by scaling transformation. Including both the dynamical displacement of phonon modes and the softening of phonon frequency, this approach yields fairly accurate results for the ground state energy. The energy splitting and Ham's reduction factor are calculated, which also generates fairly good results compared with other perturbation results. We argue that our variational wave function is valid for the weak and intermediate coupling range. 相似文献
969.
970.