N3+: Full-Dimensional Potential Energy Surface, Vibrational Energy Levels and Ground State Dynamics
Abstract
The fundamentals and higher vibrationally excited states for the N3+ ion in its electronic ground state have been determined from quantum bound state calculations on 3-dimensional potential energy surfaces (PESs) at the CCSD(T)-F12 and MRCI+Q levels of theory. The vibrational fundamentals are at 1130 cm-1 (1, symmetric stretch), 807 cm-1 (3, asymmetric stretch), and 406 cm-1 (2, bend) on the higher-quality CCSD(T)-F12 surface. For 1, the calculations are close to the estimated frequency from experiment (1170 cm-1) and previous calculationsrosmus.n3:1994 which find it at 1190 cm-1. Calculations of the vibrational states on the MRCI+Q PES are in qualitative agreement with those using the CCSD(T)-F12 PES. Analysis of the reference CASSCF wave function for the MRCI+Q calculations provides further insight into the shape of the PES and lends support for the reliability of Hartree-Fock as the reference wave function for the coupled cluster calculations. According to this, N3+ has mainly single reference character in all low-energy regions of its electronic ground state (3A'') 3d PES.