The collisional shift of a transition constitutes an important systematic effect in highprecision spectroscopy. Accurate values for van der Waals interaction 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.
U. D. Jentschura and C. M. Adhikari, "Long-Range Interactions for Hydrogen: 6P-1S and 6P-2S Systems," Atoms, vol. 5, no. 4, MDPI Multidisciplinary Digital Publishing Institute, Dec 2017.
The definitive version is available at https://doi.org/10.3390/atoms5040048
Keywords and Phrases
Hyperfine levels; Interatomic interactions; Long-range interactions; Matrix element; Quasi-degenerate states
International Standard Serial Number (ISSN)
Article - Journal
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