Quantum Electrodynamics Effects in Rovibrational Spectra of Molecular Hydrogen

Abstract

The dissociation energies from all rovibrational levels of H2 and D2 in the ground electronic state are calculated with high accuracy by including relativistic and quantum electrodynamics (QED) effects in the nonadiabatic treatment of the nuclear motion. For D2, the obtained energies have theoretical uncertainties of 0.001 cm(-1). For H2, similar uncertainties are for the lowest levels, while for the higher ones the uncertainty increases to 0.005 cm(-1). Very good agreement with recent high-resolution measurements of the rotational v = 0 levels of H2, including states with large angular momentum J, is achieved. This agreement would not have been possible without accurate evaluation of the relativistic and QED contributions and may be viewed as the first observation of the QED effects, mainly the electron self-energy, in a molecular spectrum. For several electric quadrupole transitions, we still observe certain disagreement with experimental results, which remains to be explained.

Precision measurements and test of molecular theory in highly excited vibrational states of H2 (v = 11)

“…The Q (1) and O(3) transitions share a common upper EF level, and the energy difference of 248.7329(21) cm −1 gives the ground state splitting X, v ′′ = 11, J ′′ = 1 → 3. This can be compared to the theoretical splitting derived from Komasa et al [9] of 248.731(7) cm −1 . In analogous fashion, the Q(3) and O(3) share the same lower X level, which enables the extraction of the EF, v ′ = 1, J ′ = 1 → 3 energy splitting of 61.1194(21) cm −1 .…”

“…[22], the uncertainties in the calculations [9] are five times worse for the v = 8-11 in comparison with the v = 0 level energies. Along with the previous measurements on the X, v = 12 levels in Ref.…”

“…Present developments in the ab initio theory of the two-electron neutral H 2 molecule and the one-electron ionic H + 2 molecule, as well as the respective isotopologues have advanced in accuracy approaching that of its atomic counterpart despite the increased complexity. The most accurate level energies of the entire set of rotational and vibrational states in the ground electronic state of H 2 were calculated by Komasa et al [9]. An important breakthrough in these theoretical studies was the inclusion Abstract Accurate EF 1 Σ + g −X 1 Σ + g transition energies in molecular hydrogen were determined for transitions originating from levels with highly excited vibrational quantum number, v = 11, in the ground electronic state.…”

Velocity-changing collisions in pure H2 and H2-Ar mixture

“…49 based on the approach developed by Komasa et al 85 On the other hand the thermally averaged collisional shift can be estimated from the single line shape fitting thanks to its speed dependence, however, result will be dramatically dependent on the form of assumed B S (x) function. Finally, the line intensity determined from SD e BBP 25.990 × 10 −28 cm −1 /(molecule/cm 2 ) agrees very well, within 0.04%, with the theoretical value 25.980×10 −28 cm −1 /(molecule/cm 2 ) reported in Ref.…”

VUV Fourier-transform absorption study of the Lyman and Werner bands in D2

“…1 Recently, also high-order relativistic and quantum-electrodynamic effects, i.e., molecular Lamb shifts were included in the calculations, although limited to the X 1 + g ground state. 2 For D 2 these calculations were subjected to test and confirmed in a measurement of the dissociation energy of the ground state 3 at an accuracy level of <0.001 cm −1 . For the electronically excited states of 1 + u symmetry 4 and 1 u symmetry 5 ab initio calculations have been performed, although at lower accuracy than for the ground state.…”