Ultraviolet photodissociation dynamics of HN3:: the H+N3 channel

The H + N-3((X) over tilde(2)Pi(g)) channel in the ultraviolet photodissociation of HN3 has been studied at 248.3 and 193.3 nm using the high-ii Rydberg H-atom time-of-night technique. In 248.3 nm photodissociation, center-of-mass translational energy distribution reveals a propensity toward product translation ([f(trans)] = 0.71) and N-3 bending and symmetric stretching excitation. An anisotropic product angular distribution (beta approximate to -0.8) indicates a perpendicular electronic transition and rapid dissociation on the excited-state surface. H-N bond energy is estimated: D-0(H-N-3) less than or equal to 88.7 +/- 0.5 kcal/mol. At 193.3 nm, [f(trans)] is smaller and product angular distribution is energy-dependent, suggesting multiple dissociation pathways via different electronic states. (C) 1999 Elsevier Science B.V. All rights reserved.