MP2 STUDIES OF RELATIVISTIC EFFECTS ON THE LINEAR STATIONARY-POINTS OF THE H-2-]HCL+CL AND CL+HCL-]CLH+CL REACTIONS(CL)

The influence of relativistic effects on the linear stationary points of the potential energy surfaces of the CIHCl and HCl2 systems is stud ied. Scalar relativistic effects have little influence on the geometri es and the energies at these points. Spin-orbit effects have no influe nce on the barrier of the forward reaction of H with Cl-2, but increas e the reaction energy. The total relativistic effect is an increase of the reaction energy by 2.3 kJ mol(-1). The barrier for the iso-energe tic exchange reaction of HCl with Cl is decreased by 0.5 kJ mol(-1) du e to the scalar relativistic effects. This small decrease is cancelled by the larger increase of 2.5 kJ mol(-1) due to spin-orbit effects, g iving a total relativistic effect of 2.0 kJ mol(-1).