Ground, excited and ionic states of unstable molecules

This work describes the use of several complementary gas phase methods, HeI photoelectron spectroscopy, mid-infrared absorption, and laser based spect roscopy with ion and electron detection for the investigation of ground, ex cited and ionic states of unstable molecules. The focus is on the spectrosc opy and the electronic and geometric structures of small molecules generate d for the first time in the gas phase. Comparisons are made with ab initio calculations for structures, ionisation energies and vibrational frequencie s. (C) 2000 Elsevier Science B.V. All rights reserved.