POTENTIAL-ENERGY CURVES OF GROUND AND EXCITED-STATES OF TETRA HALOMETHANES AND THE NEGATIVE-IONS

A large scale multireference configuration interaction study (involvin g up to 2.3 million configurations) of potential energy curves for gro und and excited states for dissociative electron attachment are presen ted for CCl4/CCl4-, CBr4/CBr4-, and CI4/CI4- systems. The spin-orbit c oupling in CI4/CI4- is also calculated using the relativistic configur ation interaction approach. The results agree reasonably well with the available experimental data for electron affinities, giving a confide nce in the overall quality of potential surfaces. The study leads to a better understanding of the reaction CX(4)+e-->[CX(4)](-)-->CX(3)+X(- ), which is believed to be an important step in biological processes i nvolving halocarbons.