Long-Range Interactions for Hydrogen Atoms in Excited D States

Author

Chandra M. Adhikari
Ulrich D. Jentschura, Missouri University of Science and TechnologyFollow

Abstract

Pressure shifts inside an atomic beam are among the more theoretically challenging effects in high-precision measurements of atomic transitions. A crucial element in their theoretical analysis is the understanding of long-range interatomic interactions inside the beam. For excited reference states, the presence of quasi-degenerate states leads to additional challenges, due to the necessity to diagonalize large matrices in the quasi-degenerate hyperfine manifolds. Here, we focus on the interactions of hydrogen atoms in reference states composed of an excited nD state (atom A), and in the metastable 2S state (atom B). We devote special attention to the cases n = 3 and n = 8. For n = 3, the main effect is generated by quasi-degenerate virtual P states from both atoms A and B and leads to experimentally relevant second-order long-range (van-der-Waals) interactions proportional to the sixth inverse power of the interatomic distance. For n = 8, in addition to virtual states with two states of P symmetry, one needs to take into account combined virtual P and F states from atoms A and B. The numerical value of the so-called C6 coefficients multiplying the interaction energy was found to grow with the principal quantum number of the reference D state; it was found to be of the order of 1011 in atomic units. The result allows for the calculation of the pressure shift inside atomic beams while driving transitions to nD states.

Recommended Citation

C. M. Adhikari and U. D. Jentschura, "Long-Range Interactions for Hydrogen Atoms in Excited D States," Atoms, vol. 10, no. 1, article no. 6, MDPI, Mar 2022.

The definitive version is available at https://doi.org/10.3390/atoms10010006

Department(s)

Physics

Comments

This research has been supported by the National Science Foundation (grant PHY–2110294).

Keywords and Phrases

Fine-structure-hyperfine structure mixing; Perturbation theory; Quasi-degenerate states; Van der Waals interaction

International Standard Serial Number (ISSN)

2218-2004

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2022 The Authors, All rights reserved.

Creative Commons Licensing

This work is licensed under a Creative Commons Attribution 4.0 License.

Publication Date

01 Mar 2022