An <i>Ab Initio</i> Electronic Structure Investigation of the Ground and Excited States of ScH<sup>+</sup>, YH<sup>+</sup>, and LaH<sup>+</sup>
Multireference configuration interaction (MRCI), Davidson-corrected MRCI (MRCI+Q), coupled-cluster singles, doubles, and perturbative triples [CCSD(T)], and frozen-core full configuration interaction (fcFCI) calculations were carried out using large, correlation-consistent basis sets to investigate...
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-06-01
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| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/30/11/2435 |
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| Summary: | Multireference configuration interaction (MRCI), Davidson-corrected MRCI (MRCI+Q), coupled-cluster singles, doubles, and perturbative triples [CCSD(T)], and frozen-core full configuration interaction (fcFCI) calculations were carried out using large, correlation-consistent basis sets to investigate the excited states of the Sc atom and the spin–free and spin–orbit coupled potential energy profiles, energetics, spectroscopic constants, and electron populations of low-lying states of MH<sup data-eusoft-scrollable-element="1">+</sup> (M = Sc, Y, La). The core electron correlation effects, complete basis set effects, and spin–orbit coupling effects were also evaluated. The first four electronic states of all MH<sup data-eusoft-scrollable-element="1">+</sup> are 1<sup data-eusoft-scrollable-element="1">2</sup>Δ, 1<sup data-eusoft-scrollable-element="1">2</sup>Σ<sup data-eusoft-scrollable-element="1">+</sup>, 1<sup data-eusoft-scrollable-element="1">2</sup>Π, and 2<sup data-eusoft-scrollable-element="1">2</sup>Σ<sup data-eusoft-scrollable-element="1">+</sup> with 1σ<sup data-eusoft-scrollable-element="1">2</sup>1δ<sup data-eusoft-scrollable-element="1">1</sup>, 1σ<sup data-eusoft-scrollable-element="1">2</sup>2σ<sup data-eusoft-scrollable-element="1">1</sup>, 1σ<sup data-eusoft-scrollable-element="1">2</sup>1π<sup data-eusoft-scrollable-element="1">1</sup>, and 1σ<sup data-eusoft-scrollable-element="1">2</sup>3σ<sup data-eusoft-scrollable-element="1">1</sup> single-reference electron configurations, respectively. These states of MH<sup data-eusoft-scrollable-element="1">+</sup> can be represented by the M<sup data-eusoft-scrollable-element="1">2+</sup>H<sup data-eusoft-scrollable-element="1">–</sup> ionic structure. The ground states of ScH<sup data-eusoft-scrollable-element="1">+</sup>, YH<sup data-eusoft-scrollable-element="1">+</sup>, and LaH<sup data-eusoft-scrollable-element="1">+</sup> are 1<sup data-eusoft-scrollable-element="1">2</sup>Δ<sub data-eusoft-scrollable-element="1">3/2</sub>, 1<sup data-eusoft-scrollable-element="1">2</sup>Σ<sup data-eusoft-scrollable-element="1">+</sup><sub data-eusoft-scrollable-element="1">1/2</sub>, and 1<sup data-eusoft-scrollable-element="1">2</sup>Δ<sub data-eusoft-scrollable-element="1">3/2</sub> with 55.45, 60.54, and 62.34 kcal/mol bond energies, respectively. The core electron correlation was found to be vital for gaining accurate predictions on the ground and excited state properties of MH<sup data-eusoft-scrollable-element="1">+</sup>. The spin–orbit coupling effects are minor for ScH<sup data-eusoft-scrollable-element="1">+</sup> but become substantial moving to YH<sup data-eusoft-scrollable-element="1">+</sup> and LaH<sup data-eusoft-scrollable-element="1">+</sup>. Overall, the results of this work are in good agreement with the limited set of experimental findings of MH<sup data-eusoft-scrollable-element="1">+</sup> available in the literature and will be of use for future investigations. Furthermore, the theoretical approaches, findings, and trends reported here are expected to aid studies of similar species. |
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| ISSN: | 1420-3049 |