Theoretical study of asymmetric molecular-frame photoelectron angular distributions for C 1s photoejection from CO2

We report the results of ab initio calculations of cross sections and molecular-frame photoelectron angular distributions for C 1s ionization of CO2, and propose a mechanism for the recently observed asymmetry of those angular distributions with respect to the CO^+and O^+ions produced by subsequent Auger decay. The fixed-nuclei, photoionization amplitudes were constructed using variationally obtained electron-molecular ion scattering wave functions. We have also carried out electronic structure calculations which identify a dissociative state of the CO2^++ dication that is likely populated following Auger decay and which leads to O^+ + CO^+ fragment ions. We show that a proper accounting of vibrational motion in the computation of the photoelectron angular distributions, along with reasonable assumptions about the nuclear dissociation dynamics, gives results in good agreement with recent experimental observations. We also demonstrate that destructive interference between different partial waves accounts for sudden changes with photon energy in the observed angular distributions

Ab initio study of low-energy electron collisions with tertafluoroethene, C2F4

We report the results of variational calculations of elastic electron scattering by tetrafluoroethene, C_2F_4, with incident electron energies ranging from 0.5 to 20 eV, using the complex Kohn method and effective core potentials. These are the first fully \ai calculations to reproduce experimental angular differential cross sections at energies below 10 eV. Low-energy electron scattering by C_2F_4 is sensitive to the inclusion of electronic correlation and target-distortion effects. We therefore present results that describe thedynamic polarization of the target by the incident electron. The calculated cross sections are compared with recent experimental measurements

Ab initio study of low-energy electron collisions with tertafluoroethene, C2F4

We report the results of variational calculations of elastic electron scattering by tetrafluoroethene, C_2F_4, with incident electron energies ranging from 0.5 to 20 eV, using the complex Kohn method and effective core potentials. These are the first fully \ai calculations to reproduce experimental angular differential cross sections at energies below 10 eV. Low-energy electron scattering by C_2F_4 is sensitive to the inclusion of electronic correlation and target-distortion effects. We therefore present results that describe thedynamic polarization of the target by the incident electron. The calculated cross sections are compared with recent experimental measurements

Studies of HeH: Dissociative Excitation

We have used structure and scattering calculations to determine the potential energy curves, non-adiabatic couplings and autoionization widths for the HeH system. These will be used to study a variety of processes ranging from dissociative recombination to mutual neutralization. As an example, we present our results on the direct dissociative excitation of HeH+ by electron impact via excitation to the two lowest excited states of the ion. The results are found to be in good agreement with experiment