K-SHELL PHOTOIONIZATIONS IN STRONGLY COUPLED PLASMAS

In strongly coupled plasmas, the photoionizations from the 1 s ground state of hydrogenic ions are investigated using the ion-sphere model p otential. The initial bound wave function and energy eigenvalue of the target ion are modified in the ion-sphere potential using the Ritz va riation method. The final state of the ejected photoelectron is repres ented by a plane wave solution. The Coulomb correction is considered u sing the screened Coulomb wave function with the appropriate effective charge. The K-shell photoionization cross section is obtained for the acceleration form of the matrix element because of the convenience of the calculations. The plasma screening effect is obtained as a functi on of the ion-sphere radius and photon energy. The retardation correct ion is also considered in obtaining the total K-shell photoionization cross section in strongly coupled plasmas. The plasma screening effect s on the total K-shell photoionization cross section for the ion-spher e radius, R-Z greater than or equal to 2a(Z), are found to be less tha n about 25%. It is also found that the plasma screening effect is almo st independent of the incident photon energy. (C) 1998 American Instit ute of Physics. [S1070-664X(98)00412-1].