Multireference calculations of potential energy and transition dipole moment surfaces for first and second UV absorption bands of N2O

A great deal of theoretical work has been carried out to investigate the properties of the six lowest singlet electronic states of N2O molecule: the ground state X(1)A'; the excited states 1(1)A '', 2(1)A', 2(1)A '', 3(1)A' and 3(1)A ''. Multireference configuration interaction (MRCI) approach has been used to compute the full-dimensional potential energy surfaces of the six lowest states employing aug-cc-pVQZ minus g orbital basis set. It was found that such of highly accurate potential yields excellent results of bond dissociation and vertical excitation energies in comparison with the experimental values. Several important symmetry and nonsymmetry related conical intersections in linear and bent geometries have been discussed. Of particular interest is the location of conical intersections between the 2(1)A' ((1)Delta) and 3(1)A' ((1)Pi) states, and between the 1(1)A '' ((1)Sigma(-)) and 3(1)A '' ((1)Pi) states in linear geometry, as well as conical intersection between the X(1)A' and 2(1)A' states in bent geometry. The corresponding transition dipole moment surfaces have also been computed, connecting the ground electronic state to the lowest five excited states. Detailed discussion on the vector properties of the dipole transition has been presented specifically in the vicinity of the conical intersections.