[en] Short communication

[en] Quantum-mechanical effects on electron-electron scattering cross sections are investigated in dense high-temperature plasmas. An effective pseudopotential model taking into account both quantum-mechanical effects and plasma screening effects is applied to describe electron-electron interactions in dense high-temperature plasmas. The Born approximation and the total spin states are considered to obtain high-energy electron-electron scattering cross sections. The results show that the differential scattering cross sections are significantly reduced with increasing the thermal de Broglie wavelength. It is also found that the quantum-mechanical effects are especially important at the scattering angle θ_lab=π/4

[en] A time and polarization resolved reflective interferometry measurement on femtosecond laser heated gold is presented. We deduced the electron momentum damping frequency, the conduction electron density, and finally the electron temperature in the 0.6-5 eV range in out of equilibrium, solid density warm dense gold. This allows the experimental determination of the electron-electron collision frequency variation with the electron temperature in warm dense matter conditions. The comparison with several models shows the importance of properly taking into account the d-band electrons in noble metals. (authors)

[en] We develop a Luttinger-liquid theory of the Coulomb drag of persistent currents flowing in concentric mesoscopic rings by incorporating nonlinear corrections to the electron dispersion relation. We demonstrate that at low temperatures, interactions between electrons in different rings generate an additional phase and thus alter the period of Aharonov-Bohm oscillations. The resulting nondissipative drag depends strongly on the relative parity of the electron numbers. We also show that interactions set a new temperature scale below which the linear response theory does not apply at certain values of external flux. copyright 1997 The American Physical Society

[en] For a quasi-neutral current sheet with a finite normal magnetic component the tearing mode is stabilized by the adiabatic motion of the magnetized electrons. If the current sheet is not absolutely quiescent but contains electromagnetic wave turbulence (or collisions) which pitch angle scatters the mirror-trapped electrons, the tearing mode is destabilized with a growth rate proportional to the pitch angle diffusion coefficient. For observed turbulence levels in the earth's plasma sheet the tearing growth time could be 5 min

No abstract available

[en] An explicit expression for the distribution function of excess quasiparticles is derived by taking into account electron-electron collisions in nonequilibrium superconductors. It is shown that for certain ratios of the electron-electron and electron-phonon coupling constants the nature of the phase transition may change, the dependence of the order parameter on the power of the source becoming ambiguous; moreover, diffusion instability and paramagnetism of the superconductors arise. The multiplication factor of the excess quasiparticles due to electron-electron collisions and reabsorption of phonons are calculated

No abstract available

[en] A method is developed for calculating the probability amplitude of the ionization of atoms by electrons in an electric field. The wave functions of the initial and final scattering channels are calculated in the approximation of a open-quotes frozenclose quotes ion core. The effect of the electric field on the ionization amplitude is taken into account in the first order perturbation theory for the Green function. Estimates are made of the distortion factor η_k(E), and it is shown that near the ionization threshold at a field strength E of order of 10-100 kV cm^-1 the value of η_k(E) can be large. 12 refs

[en] The electron-impact energy loss spectrum of 1,3,5,7-cyclooctatetraene has been measured at electron impact energies of 30, 50, and 75 eV, and scattering angles varying from 5⁰ to 80⁰. Three transitions with maxima at 3.05, 4.05, and 4.84 eV are identified as singlet → triplet excitations. The significance of the lowest lying of these triplet states in the quenching process of dye laser solutions (in particular rhodamine 6G) is discussed and an exciplex mechanism for triplet quenching is suggested. Singlet→singlet transitions are observed at 4.43, 6.02, and 6.42 eV. These spin-allowed transitions have been observed optically and are assigned as X ¹A₁ →¹A₂, X ¹A₁→¹E, and X ¹A₁→¹E excitations. Three new, singlet → singlet transitions are observed at 6.99, 8.41, and 9.05 eV and are tentatively assigned as the X ¹A₁→¹B₂, X ¹A₁→¹E, and X ¹A₁ →¹E, π→π* excitations. Several superexcited features between 10 and 15 eV have been observed and are believed to involve excitations to autoionizing Rydberg states