Observation of an energy shift in the S2${\mathit{p}}_{3/2}$–S2${\mathit{p}}_{1/2}$ spin-orbit splitting between x-ray photoelectron and Auger-electron spectra for the ${\mathrm{H}}_2$S molecule

The S 2${\mathit{p}}_{3/2}$–S2 ${\mathit{p}}_{1/2}$ spin-orbit splitting is measured for the free ${\mathrm{H}}_2$S molecule using both high-resolution x-ray photoelectron spectroscopy (XPS) and high-resolution photon-excited Auger-electron spectroscopy. It is found that the spin-orbit splitting differs in the two experiments by as much as 50 meV. In contrast, the Ar 2${\mathit{p}}_{3/2}$–Ar 2${\mathit{p}}_{1/2}$ spin-orbit splitting is practically the same when comparing Auger and XPS data. The origin of the shift for ${\mathrm{H}}_2$S is discussed with respect to molecular field splitting and state interference effects.