Ab initio calculations of the rovibrational states of He2N2+ Original Research Article

The low-lying rovibrational states of the 2B1 ground electronic state of He2N2+ were calculated using ab initio techniques. A 74 point potential energy surface was constructed using the CCSD(T) method coupled with a cc-pCVTZ basis set. The CCSD(T) optimised equilibrium geometry was of C2v symmetry with an RNHe bond length of 1.329 Å and a θHeNHe bond angle of 88.6°. The discrete potential energy surface was fitted using a Padé (4,5) power series expansion, yielding a (χ2)12 of 9.98 × 10−5 au. The potential function was embedded in the nuclear Schrödinger equation and solved variationally to yield the low-lying rovibrational states.