Investigation of penning ionization of NO 2 by He(2 3S) by means of an electron—ion coincidence technique

Abstract

We have investigated the Penning ionization of NO 2( 2 A 1) by He(2 3 S) by means of electron—ion coincidence measurements. It is possible to identify two entrance channels. The quartet state is essentially repulsive and gives rise to an electron energy spectrum similar to that found in photoionization. The doublet entrance channel is strongly attractive with a well depth D e of 4.8 { −0.3 +0.1 eV. Ionization out of this channel leads to very broad features in the electron energy spectrum.