Nonadiabatic relativistic correction in H$_2$, D$_2$, and HD

TL;DR

This paper presents a method to calculate nonadiabatic relativistic corrections to rovibrational energy levels of H2, D2, and HD molecules, improving agreement with experimental data and resolving previous discrepancies.

Contribution

It introduces a nonadiabatic perturbation theory approach that computes corrections using a single effective potential, enhancing accuracy and efficiency.

Findings

Results agree well with previous calculations of dissociation energies.

The method resolves discrepancies between theory and recent experiments.

Provides a unified approach for all molecular levels.

Abstract

We calculate the nonadiabatic relativistic correction to rovibrational energy levels of H$_2$, D$_2$, and HD molecules using the nonadiabatic perturbation theory. This approach allows one to obtain nonadiabatic corrections to all the molecular levels with the help of a single effective potential. The obtained results are in very good agreement with the previous direct calculation of nonadiabatic relativistic effects for dissociation energies and resolve the reported discrepancies of theoretical predictions with recent experimental results.