Classical trajectory calculations for collision-energy/electron-energy resolved two-dimensional Penning ionization electron spectra of N2, CO, and CH3CN with metastable He*(23S) atoms

Collision-energy/electron-energy resolved two-dimensional Penning ionization electron spectra (2D-PIES) of N-2, CO, and CH3CN with metastable He*(2 S-3) atoms are measured, and classical trajectory calculations with anisotropic entrance and exit potential energy surfaces are performed for these systems. Numerical qualities of the entrance potential surfaces are decisively important to understand the collisional ionization dynamics as well as to reproduce observed 2D-PIES, whereas the exit potential surfaces are less sensitive to the collisional ionization dynamics and the electron spectra except for special cases in which a deep potential well is relevant in the entrance potential surface. Ab initio calculations of both entrance and exit potentials as well as ionization widths are found to be reliable in obtaining their anisotropy and radial dependence with good quantitative accuracy. (C) 2002 American Institute of Physics.