Photodissociation dynamics of HN3 at 248 nm: a trajectory surface hopping study

The photodissociation dynamics of hydrazoic acid (HN3) at 248 nm has been studied using a quasi-classical variant of the trajectory surface-hopping (TSH) method in conjunction with Tully's fewest switches algorithm. Trajectories were integrated on-the-fly at the MRCIS(8,9)/6-31++G(d,p) level of theory. Analysis of our trajectory simulation reveals that N-2 ((X) over tilde 1 Sigma(+)(g)) + NH (a (1)Delta) as the primary major products contributing similar to 95% of the overall product formation with N-3 ((X) over tilde (2)Pi(g)) + H(S-2) as the minor products contributing the rest similar to 5%. No internal conversion (IC) from the first excited state S-1 to the ground state S-0 was observed in the photodissociation of HN3 from its first excited singlet state (S-1). Intersystem crossing (ISC) from the first excited singlet state S-1 to the lowest triplet state T-1 was predicted to be inefficient based on the calculated weak spin-orbit interactions between the states.