PHOTODISSOCIATION, CHARGE AND ATOM-TRANSFER PROCESSES IN ELECTRONICALLY EXCITED-STATES OF N-3(+)

The collinear dissociation paths for several low lying electronically excited singlet and tripler states of N-3(+) have been mapped by ab in itio calculations. It has been found that the first excited (3) Pi sta te is separated by a barrier from its dissociation asymptote, explaini ng the experimental finding that rotationally resolved photodissociati on spectra have been detected. No long-range avoided crossings between the two lowest (3) Sigma(-) and (3) Pi states have been found, implyi ng that the charge and atom transfer processes involving N+, N-2(+) an d N-2 occur at closer range. No path has been found which would allow a spontaneous charge transfer N(S-4) + N-2(+)(X(2) Sigma(g)(+)) --> N(P-3) + N-2(X(1) Sigma(g)(+)). The shapes of the calculated potential energy functions explain also that the opposite reaction is not observ ed until a threshold energy of about 2.8 eV, though it is endothermic only by 1.043 eV. The vertical excitation energies, geometries of the centrosymmetric structures, and the electronic transition moments for singlet, tripler and quintet states are given.