Pre-Born–Oppenheimer energies, leading-order relativistic and QED corrections for electronically excited states of molecular hydrogen

Abstract

For rovibronic states corresponding to the B and $B^{\prime }{}^1{\mathrm{\Sigma }}_{\mathrm{u}}^{+}$ electronic states of the hydrogen molecule, the pre-Born–Oppenheimer (four-particle) non-relativistic energy is converged to a 1–3 parts-per-billion relative precision. The four-particle non-relativistic energy is appended with leading-order relativistic, leading- and estimated higher-order quantum-electrodynamics corrections. The resulting term values referenced to the rovibronic ground state are obtained in an excellent agreement with the experimental results. Further results are reported and discussed for other rovibronic states assignable to the $C{}^1{\mathrm{\Pi }}_{\mathrm{u}}$ and the $EF,GK,$ and $HH{}^1{\mathrm{\Sigma }}_{\mathrm{g}}^{+}$ electronic states.

GRAPHICAL ABSTRACT

Keywords:

• Pre-Born–Oppenheimer
• H2 molecule
• relativistic
• QED corrections

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Financial support of the H2020 European Research Council through a Starting Grant (No. 851421) is gratefully acknowledged. DF thanks a doctoral scholarship from the ÚNKP-22-4 New National Excellence Program of the Ministry for Innovation and Technology from the source of the National Research, Development and Innovation Fund (ÚNKP-22-4-I-ELTE-51).