화학공학소재연구정보센터
Journal of Chemical Physics, Vol.110, No.7, 3411-3417, 1999
Photodissociation of N2O: J-dependent anisotropy revealed in N-2 photofragment images
Photofragment imaging is used to measure the state-specific angular distributions of N-2 produced in the ultraviolet photodissociation of N2O. 2+1 REMPI (resonance enhanced multiphoton ionization) through the a"((1)Sigma(g)(+)) state is used to ionize individual rotational states of N-2(nu=0) between J=40 and J=90 produced when N2O is dissociated by light of approximately 203 nm. The anisotropy parameter, beta, used to characterize the angular distributions of the N-2 ion images, is greater than one for the lower rotational levels probed, and decreases to approximately zero for the highest rotational levels of N-2. The positive beta parameter indicates that the products arise primarily from a parallel transition to the 2 (1)A'((1)Delta) state in the parent molecule, and the decrease in beta with increasing J of N-2 is due to increased bending in the parent N2O during dissociation. The ion images also allow us to assign transitions in a spectroscopically perturbed region of the N-2 photofragment REMPI spectrum and to reveal the production of N-2 products in the first vibrationally excited state.