Ariyarathna Isuru R
Los Alamos National Laboratory, Theoretical Division, Los Alamos, NM 87545, USA.
Molecules. 2025 Jun 2;30(11):2435. doi: 10.3390/molecules30112435.
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 (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 are 1Δ, 1Σ, 1Π, and 2Σ with 1σ1δ, 1σ2σ, 1σ1π, and 1σ3σ single-reference electron configurations, respectively. These states of MH can be represented by the MH ionic structure. The ground states of ScH, YH, and LaH are 1Δ, 1Σ, and 1Δ 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. The spin-orbit coupling effects are minor for ScH but become substantial moving to YH and LaH. Overall, the results of this work are in good agreement with the limited set of experimental findings of MH 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.
使用大的、相关一致基组进行了多参考组态相互作用（MRCI）、戴维森校正的MRCI（MRCI+Q）、耦合簇单双激发和微扰三激发[CCSD(T)]以及冻结核心全组态相互作用（fcFCI）计算，以研究Sc原子的激发态以及MH（M = Sc、Y、La）低能态的无自旋和自旋轨道耦合势能曲线、能量学、光谱常数和电子布居。还评估了核心电子相关效应、完备基组效应和自旋轨道耦合效应。所有MH的前四个电子态分别为1Δ、1Σ、1Π和2Σ，单参考电子组态分别为1σ1δ、1σ2σ、1σ1π和1σ3σ。MH的这些态可用MH离子结构表示。ScH、YH和LaH的基态分别为1Δ、1Σ和1Δ，键能分别为55.45、60.54和62.34 kcal/mol。发现核心电子相关对于准确预测MH的基态和激发态性质至关重要。自旋轨道耦合效应对于ScH较小，但对于YH和LaH则变得显著。总体而言，这项工作的结果与文献中有限的MH实验结果吻合良好，将对未来的研究有用。此外，这里报道的理论方法、发现和趋势有望有助于对类似物种的研究。
