Deexcitation cross sections of He(2 1<i>P</i>) by atoms and molecules

Abstract

The deexcitation cross sections of He(2 1P) by M (M=Kr, Xe, H2, D2, N2, CO, O2, NO, CO2, and CH4) have been obtained by a pulse radiolysis method at a mean collisional energy corresponding to room temperature. The cross sections have been explained fairly well by the Penning ionization process with a long-range dipole–dipole interaction. Bent trajectories appear to be important in the deexcitation by spherical atoms and molecules. An electron exchange process is also suggested to give an important contribution to the total decay width of the transient collision complex in highly excited autoionizing states of (HeM)*.