Dissociation Energy of Molecular Hydrogen Isotopologues

TL;DR

This paper provides highly precise theoretical calculations of the dissociation energies for all molecular hydrogen isotopologues, significantly reducing uncertainties and comparing favorably with experimental data where available.

Contribution

It presents the first comprehensive nonrelativistic, relativistic, and QED energy calculations for all hydrogen isotopologues without mass ratio expansion, improving accuracy over previous models.

Findings

Uncertainty in dissociation energy predictions is below 1 MHz.

Good agreement with experimental data for D$_2$.

Discrepancy observed for HD molecule; no data for tritium molecules.

Abstract

The nonrelativistic energy together with relativistic and quantum electrodynamic corrections for all the molecular hydrogen isotopologues (D$_2$, T$_2$, HD, HT, DT) were evaluated without expansion in the electron-nucleus mass ratio. The obtained results significantly improve the uncertainty of theoretical predictions, reaching a value below 1 MHz for the total dissociation energy. We observe good agreement with the experimental value for D$_2$ and $3\,\sigma$ discrepancy for the HD molecule, while no experimental values for the dissociation energy of molecules involving tritium have yet been obtained.