GROUND- AND LOWEST EXCITED-STATE MRDCI POTENTIAL-ENERGY SURFACES FOR THE COLLINEAR LI+HF REACTION

The collinear potential energy surfaces for the ground and lowest exci ted state of the doublet LiFH system and the evolution of the saddle p oint with the collision angle for the reaction Li+HF have been determi ned using a multiple reference single and double excitations configura tion-interaction (MRDCI) method and an extended GTO basis set. A diaba tic state analysis is made to identify and categorize the two lower ei gensolutions, obtaining that the two lower adiabatic states correspond to an avoided crossing between the two lower diabatic states. The hei ght of the collinear saddle point is found to be about 58 kJ/mol above the reactants (versus 85 kJ/mol corresponding to previous results).