Photofragmentation dynamics of H 2O 2 at 193 nm

Abstract

The photofragmentation dynamics of H 2O 2 at 193 nm have been analyzed by probing the OH products by Doppler spectroscopy using laser-induced fluorescence. The excess energy ( E av = 417 kJ mol ) appears mostly as trandational motion of the fragments with f t = 0.84. No vibrational excitation was observed ( f v < 0.003). The rotational state distribution is strongly inverted, peaking for N = 12 which results f r = 0.16. Our results indicate that previously published rotational state distributions are not nascent in character, but are perturbed by rotational relaxation. Individual fragment recoil velocities obtained from Doppler lineshapes are v = 4950 m s −1 [OH( N = 4)] and v = 4550 m s −1 [OH( N = 10)]. The effective anisotropy parameter β eff is slightly negative at high N (β eff =0.35 at N = 10).