Formation and evolution of negative ion resonances in gas-phase and condensed-phase CHFCl2

The formation of negative ions following low-energy (0-14 eV) electron impa ct is studied for CHFCl2 molecules under different phase conditions. In the gas phase, the dominant dissociative attachment channel is Cl- appearing f rom a low-energy resonance at 0.5 eV whereas from the condensed phase one o bserves F- as the most abundant channel. In the Cl- desorption yield, the l ow-energy channel (at 0.5 eV) is completely suppressed in favour of effecti ve desorption from a resonance near 8 eV. This behaviour is discussed in te rms of the different energetics between gas-phase DA and anion desorption a nd the effect of the environment on the lifetime of resonances. (C) 1999 El sevier Science B.V. All rights reserved.