Exponentially Correlated Hylleraas–Configuration Interaction Studies of Atomic Systems. III. Upper and Lower Bounds to He-Sequence Oscillator Strengths for the Resonance 1S→1P Transition

Sims JS, Padhy B, Ruiz MB (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Atoms MDPI AG

Book Volume: 11

Article Number: 107

Journal Issue: 7

DOI: 10.3390/atoms11070107

Abstract

The exponentially correlated Hylleraas–configuration interaction method (E-Hy-CI) is a generalization of the Hylleraas–configuration interaction method (Hy-CI) in which the single (Formula presented.) of an Hy-CI wave function is generalized to a form of the generic type (Formula presented.). This work continues the exploration, begun in the first two papers in this series (on the helium atom and on ground and excited (Formula presented.) states of Li II), of whether wave functions containing both linear and exponential (Formula presented.) factors converge more rapidly than either one alone. In the present study, we examined not only 1 (Formula presented.)   (Formula presented.) states but 1s2p  (Formula presented.) states for the He I, Li II, Be III, C V and O VII members of the He isoelectronic sequence as well. All (Formula presented.) energies except He I are better than previous results. The wave functions obtained were used to calculate oscillator strengths, including upper and lower bounds, for the He-sequence lowest (resonance) (Formula presented.) (Formula presented.) transition. Interpolation techniques were used to make a graphical study of the oscillator strength behavior along the isoelectronic sequence. Comparisons were made with previous experimental and theoretical results. The results of this study are oscillator strengths for the 1 (Formula presented.)   (Formula presented.) 1s2 (Formula presented.) He isoelectronic sequence with rigorous non-relativistic quantum mechanical upper and lower bounds of (0.001–0.003)% and probable precision ≤ 0.0000003, and were obtained by extending the previously developed E-Hy-CI formalism to include the calculation of transition moments (oscillator strengths).

Authors with CRIS profile

Maria Belen Ruiz Ruiz Lehrstuhl für Theoretische Chemie

Involved external institutions

National Institute of Standards and Technology (NIST) US United States (USA) (US) Khallikote Autonomous College IN India (IN)

How to cite

APA:

Sims, J.S., Padhy, B., & Ruiz, M.B. (2023). Exponentially Correlated Hylleraas–Configuration Interaction Studies of Atomic Systems. III. Upper and Lower Bounds to He-Sequence Oscillator Strengths for the Resonance 1S→1P Transition. Atoms, 11(7). https://dx.doi.org/10.3390/atoms11070107

MLA:

Sims, James S., Bholanath Padhy, and María Belén Ruiz. "Exponentially Correlated Hylleraas–Configuration Interaction Studies of Atomic Systems. III. Upper and Lower Bounds to He-Sequence Oscillator Strengths for the Resonance 1S→1P Transition." Atoms 11.7 (2023).

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