Results 1 - 10 of 16421
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[en] We propose an extension of the Ecker-Weizel approximation to treat the non-zero angular momentum bound states of a class of screened Coulomb potentials. As an illustration of our prescription, we have calculated the discrete energies Esub(n)sub(l) of the Yukawa potential, which are in excellent agreement with those of Rogers et al. (orig.)
[en] It is shown that use of realistic charge distribution leads odd moment dependence of the nuclear field isotope shift. Our expression for field isotope shift reduces to the familiar result of Seltzer for low and moderate Z, Z denoting atomic number. (orig.)
[en] We have studied the lattice structure of dusty-plasma Coulomb crystals formed in rectangular conductive grooves as a function of plasma temperature and density. The crystal appears to be made of mutually repulsive columns of grains confined by the walls of the groove. The columns are oriented along the direction of the electrode sheath electric field. A simple phenomenological model wherein the intergrain spacing results from an attractive electric-field-induced dipole-dipole force balanced by a repulsive monopole Coulomb force is consistent with observed features of the Coulomb crystal. copyright 1998 The American Physical Society
[en] Scattering on the PT-symmetric Coulomb potential is studied along a U-shaped trajectory circumventing the origin in the complex x plane from below. This trajectory reflects PT symmetry, sets the appropriate boundary conditions for bound states and also allows the restoration of the correct sign of the energy eigenvalues. Scattering states are composed from the two linearly independent solutions valid for non-integer values of the 2L parameter, which would correspond to the angular momentum in the usual Hermitian setting. The transmission and reflection coefficients are written in a closed analytic form, and it is shown that, similar to other PT-symmetric scattering systems, the latter exhibit the handedness effect. Bound-state energies are recovered from the poles of the transmission coefficients.
[en] Results are presented from measurements of the pairwise interaction potential between dust grains in plasma. The experiments were carried out with RF capacitive discharges over a wide range of dusty plasma parameters. All the experiments under analysis revealed a repulsive interaction potential that was close in shape to the screened Coulomb potential. The grain charges and the radii at which they were screened are determined
[en] The magnitude and the structure of the ion-wakefield potential below a negatively charged dust particle levitated in the plasma-sheath region have been determined. Attractive and repulsive components of the interaction force were extracted from a trajectory analysis of low-energy dust collisions in a well-defined electrostatic potential, which constrained the dynamics of the collisions to be one dimensional. The peak attraction was on the order of 100 fN. The structure of the ion-wakefield-induced attractive potential was significantly different from a screened-Coulomb repulsive potential
[en] In this short review, we describe the integrability properties of the Calogero-type perturbations of one- and two-center Coulomb problems and of the Stark-Coulomb problem. We present the explicit expressions of their constants of motion and show that these systems admit partial separation of variables.
[en] The influence of the transverse (magnetic) interaction on the dynamic properties of strongly coupled plasmas is considered. It is shown that, though magnetic interaction almost completely compensates Coulomb interaction in the high-frequency domain, the effect of the former on the Langmuir mode dispersion relation remains negligible. (orig.)
[en] Using the liquid dropled model for a dielectric cluster with two point charges, and minimizing surface and polarization energies as a function of surface shape, we calculate the energy barrier for Coulomb explosion. Results for the critical cluster size agree with numerical simulations and with experiments for Xe and CO2 clusters. (Author)
[en] The Bertaut approach associated with charge spreading so as to enhance the rate of convergence of Coulomb series in crystals is extended to the case of an arbitrary multiple spreading with a given initial spreading function. It is shown that the effect of spreading may in general be treated as a uniform transformation of space, providing that zero mean potential as a universal spatial property is sustained. As a result, electrostatic potentials driven by different orders of multiple spreading can be obtained from the same energy functional in a consistent manner. It is found that the effect of multiple spreading gives rise to more advanced forms described, for example, by simple exponential decrease, but the functional description based on a Gaussian spreading turns out to be invariant.