Theoretical vibrational terms and rotational constants for the 15N substituted isotopologues of N2O calculated using normal hyperspherical coordinates

Variational calculations of the vibrational terms Gv and rotational constants Bv of the 14N15N16O, 15N14N16O and 15N15N16O isotopologues of nitrous oxide are carried out using normal hyperspherical coordinates. The Morse-cosine potential energy surface for N2O previously determined by the authors by fitting to a set of experimental vibrational frequencies is employed. The Gv and Bv spectroscopic constants calculated for the 15N substituted isotopologues show an satisfactory agreement with those experimentally observed for a large number of vibrational bands of these isotopologues recently measured. Predicted calculated values of these spectroscopic constants for unobserved vibrational bands of the 15N substituted isotopologues are given in order to be of help in the identification and characterization of such bands, as a complement to the use of global effective Hamiltonians.