Transitions between States of the Hyperfine Structure of Antiprotonic $${}^{\mathbf{4}}$$He in Collisions with Atoms of the Medium: Interaction Ab Initio
| Autor: | G. Ya. Korenman, A. V. Bibikov, S. N. Yudin |
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| Rok vydání: | 2020 |
| Předmět: |
Physics
010308 nuclear & particles physics Ab initio General Physics and Astronomy Electron 01 natural sciences Spectral line Metastability 0103 physical sciences Potential energy surface Physics::Atomic Physics Atomic physics Perturbation theory 010306 general physics Antiprotonic helium Hyperfine structure |
| Zdroj: | Moscow University Physics Bulletin. 75:213-217 |
| ISSN: | 1934-8460 0027-1349 |
| Popis: | Collisions of the metastable antiprotonic helium atoms with the atoms of the medium cause, among other processes, transitions between hyperfine structure (HFS) states, as well as shifts and broadening of microwave M1 spectral lines. To obtain the interaction potential matrix ( $$\bar{p}$$ $$\bar{He}^{+}){-}\textrm{He}$$ , the potential energy surface (PES) is calculated by the unrestricted Hartree–Fock method with consideration of the electron correlations within the second-order of perturbation theory (MP2). With this potential, the system of equations of close coupling of the HFS channels is numerically solved; the cross sections and transition rates, shifts, and broadenings of M1 spectral lines are calculated; they are then used to solve the kinetic equation that determines the time evolution of the HFS state density matrix. The results of these calculations are compared with the experimental data and with the results of model calculations. |
| Databáze: | OpenAIRE |
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