The bound-state energy spectrum of an N-dimensional generalized exponential cosine-screened Coulomb potential is obtained by employing the N-dimensional hypervirial equations and the Hellman-Feynman theorem. The present method is shown to provide a useful 1/N expansion scheme which can be used as an alternative to the method of Mlodinow and Shatz [J. Math. Phys. 25, 943 (1984)] for the determination of the energy eigenvalues of the screened Coulomb potentials.

The large-N expansion has been used for solving the Schrödinger equation for the exponential-cosine-screened Coulomb potential. The eigenvalues of the ground state and the first excited state and the corresponding wave functions are obtained analytically up to 14 terms.

Integrating the radial part of the Fourier transform of the product of N hydrogenic orbitals results in an associated Legendre function that can be reduced to a finite series of elementary functions. This transform is found to depend on a polynomial in the wave vector k divided by a binomial in $k^2$ raised to a power that is the sum of principle quantum numbers. This form facilitates the analytical reduction of integrals arising from orthogonalization corrections in atomic processes. Transforms for the product of orbital pairs (1s,1s) through (1s,3d) are given explicitly.

The resonance-frequency shift and the energy of molecules with a large change in the permanent dipole moments between the ground and the excited levels under an intense oscillating field are investigated. It is found that the higher-order terms with respect to the Rabi frequency of the Bloch-Siegert shift cannot be neglected for molecules with a large permanent-dipole difference. Some perturbational expressions are derived, and numerical calculations are performed for various sets of parameters.

Hydrodynamic simulations of exploding copper foils, which are irradiated on one side by 1.06-μm laser light, indicate that peak axial electron-number density is more easily controlled with the split-foil target design. Results from a series of simulations with solid copper foils that range in width from 500 to 1500 Å show that while peak electron temperature and time of burnthrough can be varied, evolved electron-number densities are approximately bounded from above by 3×${10}^{20}$ particles/${\mathrm{cm}}^3$. By increasing foil thickness to 1 μm and introducing a slit on the foil axis of 100 μm width, uniform plasmas with electron-number densities on the order of 6×${10}^{20}$ particles/${\mathrm{cm}}^3$ can be generated. Essentially the same results are obtained from simulations with split selenium foils.

Céperley and Alder recently reported [Phys. Rev. A 31, 1999 (1985)] a calculation of the muon sticking probability using three-body Coulomb wave functions of the dtμ muomolecule. We comment here that such calculations require in addition the incorporation of the interplay of the nuclear reaction dynamics with the Coulomb problem.

In the paper by Weber, Bylicki, and Miksch [Phys. Rev. A 30, 270 (1984)] the ‘‘inversion effect’’ of the Hanle and rf double-resonance signals in ${\mathrm{NO}}_2$ molecules is explained with the questionable assumption of a ‘‘light-induced stability of the optically prepared state.’’ We give an alternative explanation of the ‘‘inversion effect’’ which is based on the nonstationarity of molecular perturbation by a laser and which is consistent with the present knowledge of interaction of laser light with matter.

In Phys. Rev. A 30, 270 (1984) we reported on the ‘‘inversion effect’’ which is observed when the free ${\mathrm{NO}}_2$ molecule is put into an electronically excited state by light absorption. We find no conventional explanation of this effect. The objective in Gawlik’s Comment [preceding paper, Phys. Rev. A 35, 2744 (1987)] is to point out that there may be a simple explanation of the inversion effect based on the nonstationarity of molecular perturbation by a laser field. His comment does not give the details of the calculation nor a numerical comparison with the experiment. Contrary to Gawlik, we have performed a detailed calculation which shows that his explanation cannot describe the inversion effect.

A quantum theory of quantum 1/f noise was proposed by Handel in 1975. It relates 1/f noise in currents to infrared divergences in cross sections due to, e.g., soft-photon emission. We state a number of objections to this theory. Many of the points we raise have been raised before, but have not appeared in the open literature. Our objections are partly of a practical nature, while some concern the mathematical framework of the theory.

In the cascade model of hydrodynamic turbulence, eddies are assumed to be separated into smaller ones accompanying intensity fluctuations as well as positional fluctuations. The correlation between local energy transfer rates is examined. The intensity fluctuation gives the correlation $r^{\mathrm{-}\mu }$, whereas the positional fluctuation gives the correlation $r^{\mathrm{-}(\mu +c)}$ with a roughly estimated value c≊0.4, where μ is the intermittency parameter.

A novel localized structure of traveling waves (TW’s) was observed at convection onset in ethanol-water mixtures. It is one of various possible flow patterns of TW’s which were observed. We find that for almost-one-dimensional cell geometry unique dynamics of transient behavior (in the form of two counterpropagating TW’s) can lead to various stable states.

We report measurements of heat transport and shadowgraph flow visualizations for binary mixture with separation ratio ψapeq2-0.12. Beyond a Hopf bifurcation from pure conduction, a traveling-wave state involving a single frequency develops and consists of a small number of convection rolls concentrated near the sidewall towards which it is moving. Thus about 60% of our cell is left in the pure conduction state. At a slightly larger Rayleigh number, the traveling wave becomes amplitude modulated by a second, lower frequency.

For the dielectric-breakdown model a general method is presented for calculation of the growth probability on the growing-perimeter sites of the aggregate at a surface. The growth probability is given by solving the electrostatic problem for a superconducting aggregate in the semi-infinite normal-resistor network. The electric field at the perimeter site is obtained by solving the resistor-network problem with the lattice bond-bond Green’s function. The fractal dimension D is found from the scaling assumption for the cluster-top occupancy probability.

A one-parameter, polarized, variational wave function, correlated to a projectile, is described and used as the initial state in calculations of inner-shell excitation probabilities and ionization cross sections for collisions with heavy charged particles. The Rayleigh-Ritz variational principle is used to determine the parameter. The minimized energy gives the binding effect as a function of projectile position. Existing computer codes can be adapted to incorporate the variational wave function. Early treatments of polarization as a negative binding effect give results remarkably similar to the new ones. The new results do not show the abrupt cessation of the polarization effect caused by the use of an impact-parameter cutoff in the original description. The polarization of the wave function does not give a negative binding effect. Agreement with measured K-shell ionization cross sections is improved.

The effects due to the presence of a (possibly intense) probe laser, which is used to interrogate the asymptotic excited-$m_j$-state distribution resulting from the evolution through a half-collision, are systematically studied. Experimental results are obtained which are in good qualitative agreement with predictions based on a recent theoretical treatment. Finally, a simple interpretation of the relevant physical processes involved is suggested by considering the problem within a dressed-state representation.

A Stieltjes imaging method for the calculation of molecular Auger transition rates within Wentzel’s ansatz is devised and numerically applied to the Auger emission spectrum of water vapor. Continuum orbitals are solved in the anisotropic field of the doubly ionized molecule using an extended set of $L^2$ integrable basis functions. The effects on the Auger rates of nonorthogonality between the bound orbitals (electronic relaxation) as well as of hole mixing due to the interaction of the residual final states are numerically evaluated and discussed. Comparisons are made with a previously devised atomic decomposition scheme and with experiment. The summation of Auger channel rates gives a value of 0.15 eV for the lifetime broadening of the core-hole state of water.

High-sensitivity measurements of relative partial cross sections for single, double, and triple ionization of Xe by electron impact have been carried out in the energy region from threshold to 100 eV using a crossed-beam apparatus incorporating a quadrupole mass spectrometer. The weighted sum of the relative partial cross sections at 50 eV are normalized to the total ionization cross section of Rapp and Englander-Golden to yield absolute cross-section functions. Shapes of the partial cross sections for single and double ionization are difficult to account for within a single-particle picture. Comparison of the ${\mathrm{Xe}}^{+}$ data with 4d partial photoionization cross-section measurements indicates the important role played by many-body effects in describing electron-impact ionization of high-Z atoms.

Differential cross sections for the transition K(4$P_{3/2}$→4$P_{1/2}$) induced by He and Ar have been studied both experimentally and theoretically. Calculations were performed using a full quantal close-coupling formalism. The angular distribution of the scattered atoms is measured by Doppler shift (ADDS method). The comparison with the theoretical calculations is performed on the basis of thorough kinematic analysis. In addition, the polarization effects corresponding to the experimental conditions are taken into account carefully. This allows one to test the accuracy of various interaction potentials available for the K-He and -Ar systems. The most interesting result concerns the K-He l-dependent pseudopotentials, which are found accurate to a sufficiently high level to allow good predictions of the observed differential cross-section patterns. In particular the positions and amplitudes of the cross-section oscillations at large center-of-mass scattering angles are well reproduced. The results for Ar show that the K-Ar potentials must be improved. Finally, taking the K(4P)-He fine-structure transition as an example, it has been shown how polarization effects may be used in ADDS measurements to obtain information on the dynamics of the collision process.

The charge distribution of many-electron ions (Xe,U) moving with relativistic velocities through light target foils is examined. In these targets, electron capture into the L and M shells of the ion and multiple ionization are negligible compared to one-electron stripping. Using a simple model for the stripping cross section, we show that a universal analytical expression can then be obtained for the target-thickness dependence of each charge fraction of the ion. This expression gives insight into the statistical nature of the stripping process and allows the extraction of one-electron ionization cross sections.

A study of the laser-assisted and field-free ionization cross sections of the ${\mathrm{He}}^{\mathrm{*}}$(2 ${}_{}{}^1{}_{}{}^{}S$,2 ${\mathrm{}}^3$S)+He(1 ${\mathrm{}}^1$S) collision system is presented as a function of the kinetic energy of the collision. The work of Evans et al. [Phys. Rev. A 4, 2235 (1971)] and Cohen [Phys. Rev. A 13, 86 (1976)] on the ${\mathrm{He}}_2$${\mathrm{}}^{\mathrm{*}}$ molecular system is used to calculate the value ${\sigma }_d$ of the field-free ionization cross section and then to normalize our experimental results. Knowing ${\sigma }_d$, we deduce the assisted-ionization cross section ${\sigma }_a$. These data show that within our energy range, the main process below $E_{\mathrm{c}.\mathrm{m}.\mathrm{}=50\mathrm{}}$ eV is laser-assisted ionization, whereas above this kinetic energy, it is a two-step reaction: collisional excitation followed by the photoionization of the level reached.