Resonances and the effects of interchannel coupling in the photoionization of CS_{2}
Abstract
The photoionization cross sections of CS_{2} leading to the X ^{2}Π_{g}, A ^{2}Π_{u}, B ^{2}Σ_{u}^{+}, and C ^{2}Σ_{g}^{+} states of CS_{2}^{+} have been computed including the effects of interchannel coupling in the multichannel frozen core HartreeFock approximation. The results were obtained using the iterative Schwinger variational method using a partial wave expansion up to l=120. The photoionization cross sections are obtained in the mixed dipole representation which ensures that the ThomasReicheKuhn sum rule is satisfied. We have found shape resonances in the kπ_{g} and kπ_{u} continuum channels. In particular, the kπ_{g} resonance is seen to affect dramatically both total cross sections and photoelectron asymmetry parameters in all other channels when interchannel coupling is included. The form of the resonant wave function indicates that this resonance is caused by low lying virtual d orbitals on the sulfur atoms. Using a Schwingertype iterative method we have found the position of the corresponding poles of the single channel T matrix in the complex plane. We have determined that the position of the pole is relatively insensitive to the interatomic bond lengths. This is indicative of the atomic nature of the resonant state. We have also determined cross sections and asymmetry parameters in the region of autoionization in the channel leading to the X ^{2}Π_{g} state of CS_{2}^{+}.
 Publication:

Journal of Chemical Physics
 Pub Date:
 November 1992
 DOI:
 10.1063/1.463699
 Bibcode:
 1992JChPh..97.6384S
 Keywords:

 Carbon Disulfide;
 Hartree Approximation;
 Ionization Cross Sections;
 Photoionization;
 Resonance Scattering;
 Kinetic Energy;
 Photoelectron Spectroscopy;
 Synchrotron Radiation;
 Atomic and Molecular Physics