Photodissociation Dynamics Of Nitrous Oxide Near 145 Nm: The O(S-1(0)) And O(P-3(J=2,1,0)) Product Channels

We report the study of photodissociation dynamics of nitrous oxide in the vacuum ultraviolet region, using the time-sliced velocity map ion imaging technique. Ion images of the O(S-1(0)) and O(P-3(J=2,1,0)) products were measured at nine photolysis wavelengths from 142.55 to 148.79 nm. The product channels O(S-1(0)) + N-2(X-1 Sigma(+)(g)) and O(P-3(J=2,1,0)) + N-2(A(3)Sigma(+)(u)) have been observed. For these dissociation channels, the total kinetic energy releases of the dissociated products were acquired. With vibrational structures of the N-2 coproducts partially resolved in the experimental images, the branching ratios of different vibrational states of the N-2 coproducts were determined, and the vibrational state specific anisotropy parameters (beta values) were derived. Analysis shows that the O(S-1(0)) + N-2(X-1 Sigma(+)(g)) channel is primarily formed via nonadiabatic couplings between the C ((1)Pi) state and the higher-lying D ((1)Sigma(+)) state of the N2O. A moderate rotational excitation and high vibrational excitation of N-2(X-1 Sigma(+)(g)) products have been observed through this pathway. On the other hand, for the O(P-3(J=2,1,0)) + N-2(A(3)Sigma(+)(u)) channels, where a slightly higher rotational excitation of N-2 coproducts have been observed, the possible pathway would be via nonadiabatic couplings from the C ((1)Pi) state to the lower-lying A((1)Sigma(-))state.