Nonempirical and quasi-classical approaches to the calculation of the electronic transition dipole moments

Abstract

The dependence of the electronic transition dipole moment on the internuclear separation is calculated nonempirically for the Meinel band of the N 2 + molecular ion using the Gaussian 98 software package with different basis sets. The results are compared with the dependences obtainedby the semiempirical methods. The basic relationships of the R-centroid method are derived, and the quasi-classical nature of this method is demonstrated. It is confirmed that the dependence of the electronic transition dipole moment on the internuclear separation is described most reliably by using the semiempirical methods. The vibronic transition dipole moment is shown to be an oscillating function of the vibrational quantum number v1 (with v2=const) or v2 (with v1=const).