THEORETICAL CALCULATIONS OF THE QUARTET POTENTIAL-ENERGY SURFACES IN THE NH-2 SYSTEM( +H)

The quartet potential energy surfaces of the NH+((4) Sigma(-))+H-2((1) Sigma(g)(+)) system are studied using ab initio and DIM model calcula tions. While there is a reaction path downhill towards H-3(+), the for mation of NH2+(B-3(2)) seems to be characterized by a large activation energy barrier. In C-2v configurations, the estimate for the energy b arrier height was determined to be about 1.9 eV with respect to the en ergy of the separated species. No substantial reduction of the barrier height through symmetry relaxation could be found. A further typical feature is that the quartet states exhibit a number of crossings with low-lying doublet states, occurring mainly in the vicinity of the ener gy barrier.