Estimation of Lamb-shift effects for molecules: Application to the rotation-vibration spectra of water

An approach for approximating Lamb shifts, the leading quantum electrodynamical (QED) effect, in light molecules is presented. The scaled molecular energies were employed for the evaluation of lamb shift as a function of geometry. Results show QED effects on the rovibrational states of water to be larger than present experimental uncertainties, and one order of magnitude smaller than current computational uncertainties.