THE N2H+-HE INTERMOLECULAR POTENTIAL ENERGY SURFACE - A VIBRATIONAL ADIABATIC CORRECTION

摘要

This paper presents a method for constructing computationally cheap adiabatically corrected ab initio potential energy surfaces (PES) for intermolecular vibrational states. The approach reasonably reproduces previously published experimental data for the N2H+-He complex in the ground and excited intramolecular vibrational states. A comparison made between a set of intermolecular PES's with the N2H+ core frozen into the equilibrium geometry and a set where the N-H+ stretch is averaged demonstrates the importance of including this motion. This is also reflected in a considerable improvement in the agreement between the experimental and the calculated intermolecular bending and stretching frequencies and the origin red shift (nu(b,calc)=117.9 cm(-1) nu(s,calc)=165.2 cm(-1), Delta nu(calc)= -93.0 cm(-1)). A comparison is also made between the cm Born-Oppenheimer angular radial separation (BOARS) angular average of the adiabatically corrected PES and the previously published rotational Rydberg-Klein-Rees (RRKR) PES. The results indicate that the two-dimensional nu(NH)=1 PES has a qualitatively correct well depth and dissociation energy (D-e=684.7 cm(-1); D-0=433.6 cm(-1)). (C) American Institute of Physics. [References: 35]