Penning ionization electron spectra of pyrene, chrysene, and coronene in collision with metastable He(2 3S) atoms in the gas phase.

摘要: Penning ionization electron spectra (PIES) of pyrene (C(16)H(10)), chrysene (C(18)H(12)), and coronene (C(24)H(12)) in the gas phase are recorded using metastable He(*)(2 (3)S) atoms. The assignments PIES presented based on outer valence Green's function calculations with correlation consistent polarized triple-zeta basis sets exterior density contributing molecular orbitals. definite positions all pi bands identified making use large cross sections. Broad observed low-electron-energy regions for ascribed to processes non-Koopmans types from sigma anisotropic interaction potential energy surfaces colliding systems obtained ab initio model potentials related similar valences Li(2 (2)S) + C(16)H(10), C(18)H(12), C(24)H(12), respectively. attractive well depths out-of-plane directions found be between these molecules, repulsive walls embrace in-plane perimeters uniformly. Collision dependencies partial sections negative peak shifts support interactions. Effects thermal populations low-frequency vibrational modes estimated minor one-electron processes.