Long-Range Interactions for Hydrogen: 6P-1S and 6P-2S

TL;DR

This paper calculates van der Waals interaction coefficients for excited hydrogen atoms, focusing on 6P-1S and 6P-2S interactions, to improve high-precision spectroscopic measurements by understanding systematic frequency shifts.

Contribution

It provides detailed calculations of long-range interactions involving quasi-degenerate states in hydrogen, aiding accurate systematic correction in precision spectroscopy.

Findings

Calculated interaction coefficients for 6P-1S and 6P-2S hydrogen states.

Demonstrated the applicability of the non-retarded approximation over wide distances.

Highlighted the significance of quasi-degenerate states in dipole-dipole interactions.

Abstract

The collisional shift of a transition constitutes an important systematic effect in high-precision spectroscopy. Accurate values for van der Waalsinteraction coefficients are required in order to evaluate the distance-dependent frequency shift. We here consider the interaction of excited hydrogen 6P atoms with metastable atoms (in the 2S state), in order to explore the influence of quasi-degenerate 2P, and 6S states on the dipole-dipole interaction. The motivation for the calculation is given by planned high-precision measurements of the transition. Due to the presence of quasi-degenerate levels, one can use the non-retarded approximation for the interaction terms over wide distance ranges.