Molecular properties calculations using the q-integral method

Abstract

The q-Integral method, based on the q-Exponential function, has been recently introduced as an alternative approach to calculate the two-electron integrals which appear in ab initio atomic and molecular quantum mechanical calculations. The advantage of this procedure is that the CPU time for calculating of two-electron integrals is substantially reduced when compared with the usual one. The objective of this work is to investigate the accuracy of the q-Integrals as a function of the internuclear distance for molecular systems. To this purpose we employed the q-Integrals to construct the potential energy surface (PES) for the H2 molecule and used the PES to determine the rovibrational levels and spectroscopic constants of the molecule, which are properties very sensitive to the form of the PES. The results obtained are in good agreement with the ones obtained through the standard procedure of calculating the two-electron integrals, implying that the q-Integral method is accurate enough to be used in any molecular quantum mechanical calculation. © 2008 Wiley Periodicals, Inc.