The negative ion states of c-C4F8

Multiple negative ion states account for three different positive electron affinities, Ea of c-C4F8 reported in the literature. From published data and a kinetic model the following are obtained: anion neutral partition function ratios; Log½Qanð0Þ ZK3:2ð3Þ, Log½Qanð1Þ Z0:0ð3Þ and Log½Qanð2Þ Z0:0ð3Þ; electron affinities Ea(0)Z1.05(8), Ea(1)Z0.66(3) and Ea(2)Z0.50(5) eV; activation energies for electron attachment E1(0)Z0.25(2), E1(1)Z0.02(2) and E1(2)Z0.00 eV. The electron affinities correspond to the lowest unoccupied molecular orbitals A2uZK0.75 eV and two degenerate Eu K0.42 eV. Semi-empirical multiconfiguration configuration interaction calculations using the CURES-EC procedure support the Ea. Bond dissociation energies, frequencies and internuclear distances are calculated for the neutral and the anions. Herschbach ionic Morse person empirical curves are calculated with these values and electron impact data. q 2004 Elsevier B.V. All rights reserved