Nonadiabatic effects in auger-induced ionic desorption

We examine the role of Galilean invariance in a nonrelativistic theory of pions and nucleons. We define a nonrelativistic pion-nucleon interaction $h$ as one which in perturbation theory gives the same matrix for a physical reaction as the limit of small nucleon velocities of the relativistic matrix. The latter matrices are always Galilean invariant, but this does not require that $h$ be Galilean invariant. If pion emission or absorption occurs from a nucleon moving in a potential, then the Galilean correction term can be shown to be ambiguously of order $\frac{v}{c}$ or of order $\frac{{v}^{2}}{{c}^{2}}$. We show that $h$ cannot always reproduce the nonrelativistic limit of a relativistic matrix. Finally, we suggest that pion production by nucleons on nuclei with excitation of giant dipole and quadrupole states may be particularly sensitive to the presence of a Galilean correction term in the production matrix.NUCLEAR REACTIONS Nonrelativistic form of pion-nucleon interaction.

A Lagrangian approach to the theory of gravito-magnetofluid systems

Noninertial transformations on time–position–momentum–energy space {t, q, p, e} with invariant Born–Green metric and the symplectic metric −de ∧ dt + dp ∧ dq are studied. This group of transformations contains the Lorentz group as the inertial special case and, in the limit of small forces and velocities, reduces to the expected Hamilton transformations leaving invariant the symplectic metric and the nonrelativistic line element ds2 = −dt2. The transformations bound relative velocities by c and relative forces by b. Spacetime is no longer an invariant subspace but is relative to noninertial observer frames. In the limit of b → ∞, spacetime is invariant. Born was lead to the metric by a concept of reciprocity between position and momentum degrees of freedom and for this reason we call this reciprocal relativity. For large b, such effects will almost certainly only manifest in a quantum regime. Wigner showed that special relativistic quantum mechanics follows from the projective representations of the inhomogeneous Lorentz group. Projective representations of a Lie group are equivalent to the unitary representations of its central extension. The same method of projective representations for the inhomogeneous group is used to define the quantum theory in the noninertial case. The central extension of the inhomogeneous group is the cover of the quaplectic group . is the Weyl–Heisenberg group. The group, and the associated Heisenberg commutation relations central to quantum mechanics, results directly from requiring projective representations. A set of second-order wave equations result from the representations of the Casimir operators.

A method to find discrete solitons in nonlinear lattices is introduced. Using nonlinear optical waveguide arrays as a prototype application, both stationary and traveling-wave solitons are investigated. In the limit of small wave velocity, a fully discrete perturbative analysis yields formulas for the mode shapes and velocity.

The electron transport through an energy transmission spectrum between two reservoirs with different temperatures and chemical potentials is studied. The heat flow carried by the electrons is obtained. Taking into account the radiative heat leaks between the two electron reservoirs, the performance parameters of the heat pump are derived by numerical calculation. The performance characteristic curves of the heat pump are plotted. The influence of the heat leaks, the position of resonance energy level and the width of the level on the operation performance of the heat pump is analyzed. When the width of resonance energy level is infinitely small, the coefficient of performance may reach the value of Carnot heat pump.

Classical theory of collective motion in the large amplitude, small velocity regime

We present a systematic study of the noncommutative interaction of gravitational waves with matter at the quantum mechanical level in the long wavelength and small velocity limit. In particular, the noncommutative quantum dynamics of the Landau's problem is employed to measure the transmission amplitudes in terms of the Riemann's tensor elements by a gravitational wave in linearized approximation. It turns out that the Hamiltonian of the charged particles derived based on DeWitt's approach is valid by the deformed electromagnetic fields.

The Stark effect of localized electronic centres is reviewed by using a few selected examples of impurity centres or simple defects. Important information on the symmetry of centres and on the position of energy levels is obtained through the electric-field-induced absorption changes. Typical results are summarized for the Stark effect on the zerophonon lines and on the broad absorption band of point defects in ionic crystals and of impurities in semiconductors.

The incompressible resistive ballooning mode equation that retains the effects of the centrifugal force due to toroidal plasma rotation is derived. In the small rotation velocity limit, the static results are recovered. For large rotation velocity the model scales linearly with resistivity and is driven by the interaction of the curvature and the centrifugal force with the radial pressure and mass density gradients, respectively.

Experimental data on the positions and widths of the vibrational energy levels of the C 3Πg Rydberg state of molecular oxygen are interpreted. The energy levels are described as resonances in the elastic scattering of oxygen atoms in the open 1 3Πg valence state caused by a coupling to the closed C 3Πg Rydberg state. The coupled scattering equations are set up with an empirical valence potential energy curve and Rydberg-valence interaction potential and it is shown that the energy level positions and widths can be reproduced by an interaction of 63 meV and a potential energy curve that crosses the Rydberg curve on the attractive part of its outer limb.

The author has been commissioned by the International Hydraulics Research Association to draw up for the Development of diversion tunnels for rivers carrying drifting solids. The study examines the present state of the techniques involved in these problems. - The paper also examines the hydraulics and civil engineering techniques concerned, in particular with the traditional delicate balance between the sometimes quite difficult theoretical concepts and purely empirical approaches. The paper studies the different approaches adopted in this regard to the design and execution of a diversion tunnel, recently built on the Rhine river (Strasbourg dam). Although progress is made continuously, the traditional approaches are by no means discredited, and one is faced with the usual problems of (cutoff) below-average pressures and energy waste. The major improvements basically lie in the use of modern construction techniques, e.g., for installing waterproof grout curtains in the ground (cutoff) for systems to minimise wear on concrete aprons. In addition, there has been a trend in the gates used towards a well defined type : sector gates with flaps. The paper discusses the tertiary techniques, an expression which covers the many activities involved in the daily operation of facilities including among others : - maintenance of equipment (leakproof quality of gates), access, - elimination of floating debris. i.e., any activity into which experience enters. Substantial progress has been achieved in the analysis of this type of problem. Automatic systems can now be used for many current operation. Such as operation of gates, cleaning of grates. - Questions relating to the elimination of solids are considered, of course, on the basis of the laws governing their movement. The example of one of the largest facilities for eliminating suspended solids for diverting a maximum flow of 460 m3/sec from the Colorado river for hydro-agricultural purposes provides evidence of the cost involved in this type of project, and therefore of the magnitude of the problems which designers try to avoid when building them. The paper thus focusses on the problems of travelling solids because of the many effects they have on the type of facility examined. The following developments can be observed as regards drifting : confidence in conventional formulae is diminishing, and the too rare comparisons of these formulae with experimental results show that they overkill Whereas the present theory has it that serious difficulties should be encountered downstream from diversions of substantial flow (raising of the beds), they virtually never occur in practice, despite the number of books examined by the author. In his view, the explanation is that the present theories are all based on results provided by models and the hypotheses on which these models have been formulated could be inaccurate. In particular, paving phenomena - or the change in the size of the material forming the bed-could have a considerable effect on the river. The current theoretical approach to suspended substances travelling in the water is somewhat rigid, and is perhaps based on over-simplistic hypotheses. In any event, it does not allow the treatment of some fundamental aspects encountered when setting the dimension of facilities such as sand traps. These conclusions are fully in line with those reached at the seminar organised by the River Hydraulics Committee of the AIRH in Lisbon in June 1982, on the Needs for Research in River Hydraulics. On-site measurement of the two types of drifting mentioned is the only way of enhancing the present standard of knowledge about the transport of solids. The paper ends by underlining that, although there has been some progress in the study and construction of diversion tunnels, much more needs to be done to understand the basic mechanisms. Until then, a systematic study of existing diversion tunnels would allow either research on the motion of solids to be carried out or would provide examples on which the study of new facilities could be based. The French Version of the Directives should be ready before end 1983, followed by the English at an as yet undetermined date.

The interaction of conduction and valence bands in narrow gap semiconductors such as InSb and HgCdTe influences the position and width of subband energy levels in space-charge layers. While a nonzero width can only occur if electrons from the conduction band can tunnel into approximately degenerate states of the valence band the level shifts due to band mixing are always present. We present a Green's function treatment which allows in a simple way to discuss the dependence of band mixing effects on the parameters of thek·p-Hamiltonian in particular the band gap. The essential qualitative feature of the level shifts is adecrease of subband energy separation withdecreasing effective mass. This agrees with recent experimental results for Hg1-x Cd x Te.

Ultrafast electrical control of optical polarization in hybrid semiconductor structure

It is shown that there are several examples of impurity ions in ionic host crystals all of whose localized excited states lie above the ionization energy of the impurity in the crystal (${\mathrm{SrF}}_{2}$:${\mathrm{Yb}}^{2+}$, ${\mathrm{BaF}}_{2}$:${\mathrm{Eu}}^{2+}$, and others). Excitation of the localized states followed by relaxation leads to a lowest excited state in which the electron resides in the host lattice while the hole remains trapped on the impurity ion. Heretofore unexplained luminescence bands result from the radiative decay of this ``impuirty trapped exciton.''

We have considered the resonant Josephson tunneling in SIS junctions with a localized state in the interlayer for an arbitrary relation between the width of the resonant level and the superconducting gap and for arbitrary barrier thickness. The analysis was carried out in the framework of the Bogolubov-de Gennes equations. For the case of short junctions and high barriers our results coincide with the results of Beenakker and van Houten theory. The obtained results can be applied for explanations of the properties of HTS Josephson junctions.