The negative ion states of c-C4F8

Multiple negative ion states account for three different positive electron affinities, E-a of c-C4F8 reported in the literature. From published data and a kinetic model the following are obtained: anion neutral partition function ratios; Log[Q(an)(0)] = -3.2(3), Log[Q(an)(1)] = 0.0(3) and Log[Q(an)(2)] = 0.0(3); electron affinities E-a(0) = 1.05(8), E-a(1) = 0.66(3) and E-a(2) = 0.50(5) eV; activation energies for electron attachment E-1(0)=0.25(2), E-1(1)= 0.02(2) and E-1(2)= 0.00eV. The electron affinities correspond to the lowest unoccupied molecular orbitals A(2u) = -0.75 eV and two degenerate E-u -0.42 eV. Semi-empirical multiconfiguration configuration interaction calculations using the CURES-EC procedure support the E-a. Bond dissociation energies, frequencies and intemuclear distances are calculated for the neutral and the anions. Herschbach ionic Morse person empirical curves are calculated with these values and electron impact data. (C) 2004 Elsevier B.V. All rights reserved.