We investigated the molecular structure and spectroscopic properties of the charged system (FH) in interaction with a helium atom using an quantum chemistry approach in Jacobi coordinates. Our study focused on the ground state XΠ of (FH) with various theoretical methods including UCCSD, UCCSD(T) and UCCSD(T)-F12, alongside basis sets like aug-cc-pVnZ (n = T, Q, 5, and 6) and cc-pVQZ-F12. We evaluated how these methods and basis sets affect the minimum energies We assessed the impact of the methods, basis sets, and extrapolation approaches on the minimum energies. Potential energy surfaces (PES) were generated using the correlated UCCSD(T)-F12 method with cc-pVQZ-F12 for hydrogen and fluorine, and cc-pVQZ-F12/optri for helium. These surfaces, considering spin-orbit coupling, are degenerate for linear geometries (θ=0° and θ=180°) of the (FH+)-He complex and correlate with the doubly degenerate XΠ state of (FH). Our results reveal a strong anisotropic character at short and intermediate distances and a quasi-isotropic character upon dissociation into FH and He. We compared the spectroscopic parameters of the (FH)-He complex with existing theoretical data, finding that the linear arrangement exhibits the highest stability, consistent with previous results for similar complexes. This conclusion is supported by the Milliken atomic charge distribution and a three-dimensional map of the Molecular Electrostatic Potential. Additionally, we used the LEVEL program, to calculate the bound rovibronic levels of the (FH)-He complex for angular momentum values Ω=1/2 and Ω=3/2. Utilizing our results and a general interpolation approach based on the Reproducing Kernel Hilbert Space method, we generated contour maps illustrating the analytical potential for the (FH)-He system. These findings will be employed to study the stabilities, geometries, energetics, and structures of the FH charged system within helium clusters.

中文翻译：

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带电系统 (FH+) 与 He 原子之间相互作用的从头算研究


我们使用雅可比坐标中的量子化学方法研究了带电系统 (FH) 与氦原子相互作用的分子结构和光谱特性。我们的研究重点是 (FH) 的基态 XΠ，采用各种理论方法，包括 UCCSD、UCCSD(T) 和 UCCSD(T)-F12，以及 aug-cc-pVnZ (n = T、Q、5 和6) 和cc-pVQZ-F12。我们评估了这些方法和基组如何影响最小能量 我们评估了这些方法、基组和外推方法对最小能量的影响。使用相关的 UCCSD(T)-F12 方法生成势能面 (PES)，对于氢和氟使用 cc-pVQZ-F12，对于氦气使用 cc-pVQZ-F12/optri。考虑到自旋轨道耦合，这些表面对于 (FH+)-He 复合体的线性几何形状 (θ=0° 和 θ=180°) 是简并的，并且与 (FH) 的双简并 XΠ 态相关。我们的结果揭示了短距离和中距离处的强烈各向异性特征以及解离成 FH 和 He 时的准各向同性特征。我们将(FH)-He配合物的光谱参数与现有理论数据进行了比较，发现线性排列表现出最高的稳定性，与之前类似配合物的结果一致。这一结论得到了美利肯原子电荷分布和分子静电势三维图的支持。此外，我们使用 LEVEL 程序来计算角动量值 Ω=1/2 和 Ω=3/2 的 (FH)-He 复合物的束缚振动电子能级。利用我们的结果和基于再现核希尔伯特空间方法的通用插值方法，我们生成了等高线图，说明了 (FH)-He 系统的分析潜力。 这些发现将用于研究氦团簇内跳频带电系统的稳定性、几何形状、能量学和结构。