Quantum Electrodynamics Effects in Rovibrational Spectra of Molecular Hydrogen.

Abstract

Dissociation energies from all rovibrational levels of H2 and D2 in the ground electronic state were computed at high precision by incorporating relativistic corrections and quantum electrodynamic (QED) effects into a nonadiabatic framework for nuclear motion. Theoretical uncertainties reached 0.001 cm⁻¹ for D2 and similarly low values for the lowest H2 levels, rising to 0.005 cm⁻¹ for higher levels. Computed values showed strong agreement with high-resolution experimental measurements of v=0 rotational levels of H2, including states with large angular momentum quantum number J. This agreement is interpreted as the first spectroscopic observation of QED contributions—primarily electron self-energy—in a molecular system. Discrepancies persisting for certain electric quadrupole transitions remain unresolved.

Mechanism

Relativistic and QED corrections, particularly electron self-energy, were incorporated into nonadiabatic nuclear motion calculations, enabling high-accuracy reproduction of rovibrational dissociation energies in H2 and D2.