QED effects in molecules: test on rotational quantum states of H$_2$

TL;DR

This study experimentally tests quantum electrodynamic effects in molecular hydrogen's rotational states using high-precision spectroscopy, confirming theoretical predictions with high accuracy.

Contribution

It provides the first high-precision experimental validation of QED effects on rotational energy levels in H₂, matching advanced theoretical calculations.

Findings

QED and relativistic effects up to 0.13 cm$^{-1}$ were measured.

Experimental results agree with recent theoretical calculations.

High-precision Doppler-free spectroscopy achieved 0.005 cm$^{-1}$ accuracy.

Abstract

Quantum electrodynamic effects have been systematically tested in the progression of rotational quantum states in the $X ^{1}\Sigma_{g}^{+}, v=0$ vibronic ground state of molecular hydrogen. High-precision Doppler-free spectroscopy of the $EF ^{1}\Sigma_{g}^{+} - X ^{1}\Sigma_{g}^{+}$ (0,0) band was performed with 0.005 cm$^{-1}$ accuracy on rotationally-hot H$_2$ (with rotational quantum states J up to 16). QED and relativistic contributions to rotational level energies as high as 0.13 cm$^{-1}$ are extracted, and are in perfect agreement with recent calculations of QED and high-order relativistic effects for the H$_2$ ground state.