# Photodissociation of N_{2}O. I. Ab Initio Potential Energy Surfaces for the Low-Lying
Electronic States X̃ ^{1}A‘, 2 ^{1}A‘, and 1 ^{1}A‘ ‘

journal contribution

posted on 24.11.1999, 00:00 by Alex Brown, Pedro Jimeno, Gabriel G. Balint-KurtiAdiabatic potential energy surfaces of the three lowest lying singlet states, X̃

^{1}A‘ 2^{1}A‘, and 1^{1}A‘ ‘, of N_{2}O have been computed as a function of the*R*_{N}_{2}_{-}_{O}bond distance and the Jacobi angle. The calculations are performed using the complete-active-space self-consistent field (CASSCF) and the multireference configuration interaction (MRCI) electronic structure methods. It is shown that there is a wide avoided crossing between the ground, X̃^{1}A‘, and lowest excited, 2^{1}A‘, electronic state. This avoided crossing is thought to give rise to a seam of conical intersection at other N−N separations. Both excited state surfaces display important conical intersections at linear geometries. The transition dipole moment surfaces for the two excitation processes (2^{1}A‘ ← X̃^{1}A‘ and 1^{1}A‘ ‘ ← X̃^{1}A‘) are also presented. These calculations provide the basic data needed to compute the dynamics of the N_{2}O +*h*ν → N_{2}+ O(^{1}D) photodissociation process for photon frequencies in the range 5.2 eV (240 nm) to 7.3 eV (170 nm).