Ariyarathna Isuru R, Leiding Jeffery A, Neukirch Amanda J, Zammit Mark C
Physics and Chemistry of Materials (T-1), Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Phys Chem Chem Phys. 2025 Jan 15;27(3):1402-1414. doi: 10.1039/d4cp03296a.
In the present work, we studied 27 FeH and 6 FeH electronic states using multireference configuration interaction (MRCI), Davidson-corrected MRCI (MRCI+Q), and coupled cluster singles doubles and perturbative triples [CCSD(T)] wavefunction theory (WFT) calculations conjoined with large quadruple- and quintuple- quality correlation consistent basis sets. We report their potential energy curves (PEC), energy related properties, spectroscopic parameters, and spin-orbit couplings. Dipole moment curves (DMC) and transition dipole moment curves (TDMC) of several low-lying electronic states of FeH and FeH are also introduced. The ground state of FeH is a single-reference XΔ (6σ7σ3π1δ) with an adiabatic of ∼52 kcal mol, which is in agreement with the experimental value. The states with the largest adiabatic binding energies of FeH (Π and Δ) are multireference in nature with an approximate of 22 kcal mol. We used CCSD(T) of the FeH(XΔ) to assess the density functional theory (DFT) errors associated with a series of functionals that span multiple rungs of Jacob's ladder of density functional approximation (DFA) and observed a general trend of improving when moving to more expensive functionals at the higher rungs. We expect weak spectral bands to be produced from the low-lying electronic states of FeH and FeH due to their lower transition values. Lastly, we present results for the total internal partition function sums (TIPS) of FeH and FeH, which have not been presented in the literature before.
在本工作中，我们使用多参考组态相互作用（MRCI）、戴维森校正的MRCI（MRCI+Q）以及耦合簇单双激发和微扰三激发[CCSD(T)]波函数理论（WFT）计算，并结合大的四重和五重质量相关一致基组，研究了27个FeH和6个FeH电子态。我们报告了它们的势能曲线（PEC）、能量相关性质、光谱参数和自旋轨道耦合。还介绍了FeH和FeH几个低电子态的偶极矩曲线（DMC）和跃迁偶极矩曲线（TDMC）。FeH的基态是单参考XΔ（6σ7σ3π1δ），绝热能约为52 kcal/mol，与实验值一致。FeH绝热结合能最大的态（Π和Δ）本质上是多参考的，绝热能约为22 kcal/mol。我们使用FeH(XΔ)的CCSD(T)来评估与一系列跨越密度泛函近似（DFA）雅各布阶梯多个梯级的泛函相关的密度泛函理论（DFT）误差，并观察到当转向更高梯级更昂贵的泛函时，误差有普遍改善的趋势。我们预计由于FeH和FeH低电子态的跃迁能值较低，会产生弱光谱带。最后，我们给出了FeH和FeH的总内部分配函数和（TIPS）的结果，这在以前的文献中尚未报道过。
