Accession Number : ADA185686

Title :   Photoionization of Atoms and Ions: Application of Time-Dependent Response Method within the Density Functional Theory.

Descriptive Note : Interim rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON DC

Personal Author(s) : Gupta, U ; Davis, J ; Blaha, M

PDF Url : ADA185686

Report Date : 13 Oct 1987

Pagination or Media Count : 40

Abstract : The photoionization cross-section of several atoms (Ar, Xe, Rn, Cs) and ions (Ne-like Ar, H-like and Li-like C) of experimental interest are calculated using the time-dependent response scheme within the framework of local density functional method (DFM). The cross-sections for rare gas atoms calculated using this method agree very well with the experimental data; whereas conventional independent particle model, calculations do not. The polarization effect of the atom brought about by the incident time-varying radiation field is shown to be important in describing observed results. Unlike the independent particle model, this effect effect is treated adequately in the DFM. To study the effect plasma density and temperature on the photoionization cross-section, calculations were also done for the ions mentioned above at various densities and temperatures. For computational simplicity, a simplified model of self-consistent finite temperature DFM was used in which the long range part of the ionic potential was taken as the Debye-screened potential. These calculations were compared with the isolated ion calculations (without any plasma effect). With increasing plasma density, significant shifts of the ionization threshold as well as substantial modifications of photoionization cross-section are obtained. This points out the need for incorporating the effect of surrounding plasma in realistic modeling of atomic properties for dense plasmas.

Descriptors :   *PHOTOIONIZATION, ATOMIC PROPERTIES, ATOMS, CONSISTENCY, CROSS SECTIONS, DENSE GASES, DENSITY, EXPERIMENTAL DATA, IONIZATION, IONS, ISOLATION, LONG RANGE(DISTANCE), LONG RANGE(TIME), MODELS, MODIFICATION, PARTICLES, PLASMAS(PHYSICS), RARE GASES, RESPONSE, SIMPLIFICATION, TEMPERATURE, THEORY, THRESHOLD EFFECTS, TIME DEPENDENCE, ARGON, XENON, RADON, CESIUM, CARBON

Subject Categories : Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE