Six-dimensional potential energy surface and rotation-vibration energy levels of HNCO in the ground electronic state

Abstract

A six-dimensional potential energy surface based on CCSD(T)/cc--pCVQZ ab initio energy points was developed for HNCO in the 1A??ground electronic state and used to calculate rotation?vibration energy levels for J?5. The barrier to linearity was computed to be 1834 cm-1 for the angle HNC and 336 cm-1 for the angle NCO. The fundamental transitions were obtained for the main form and four isotopic variants of HNCO. The state mixing v3/2v6 was identified with the help of an adiabatic projection scheme.