Abstract The bond length, electronic term symbols, bond dissociation energies (BDEs), and spectroscopic parameters of numerous low-lying electronic states of diatomic tungsten carbide (WC) have been calculated at a high level of theory. The calculations were done by using the Internally-Contracted multi-reference wave function IC-MRCI/aug-cc-pV5Z(-PP) approach. Davidson corrections were also included using the MRCI + Q method. Zero-point vibrational energy (ZPE) corrections, spin–orbit interactions, and relativistic effects are also included. The bond dissociation energy, equilibrium internuclear distance and the harmonic vibrational frequency of the ground electronic state WC(X3Δ) are computed to be D0 = 5.26 eV, Re = 1.714 A and ωe = 979 cm−1, respectively. The energies of the lowest vibrational levels (v = 0, 1, 2 and 3) of WC(X3 Δ) are computed to be (0.00, 979.7, 1948.9, 2903.6 cm−1); their rotational constants, Bv, are also computed as (0.50717, 0.50966, 0.49990 and 0.49626 cm−1), respectively. Spectroscopic parameters (ωe, ωexe, Be and αe) and equilibrium bond lengths (Re) for several Λ-S and Ω bound states of WC are also provided in this work. These results are in excellent agreement with the available experimental data.

中文翻译：

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双原子碳化钨的计算光谱，WC

摘要 双原子碳化钨 (WC) 的众多低位电子态的键长、电子术语符号、键解离能 (BDE) 和光谱参数已在高水平理论计算。计算是通过使用内收缩多参考波函数 IC-MRCI/aug-cc-pV5Z(-PP) 方法完成的。使用 MRCI + Q 方法也包括戴维森校正。还包括零点振动能量 (ZPE) 校正、自旋轨道相互作用和相对论效应。计算出的键解离能、平衡核间距离和基电子态 WC(X3Δ) 的谐波振动频率分别为 D0 = 5.26 eV、Re = 1.714 A 和 ωe = 979 cm-1。最低振动能级的能量 (v = 0, 1, WC(X3 Δ) 的 2 和 3) 计算为 (0.00, 979.7, 1948.9, 2903.6 cm-1)；它们的旋转常数 Bv 也分别计算为 (0.50717、0.50966、0.49990 和 0.49626 cm-1)。这项工作还提供了 WC 的几个 Λ-S 和 Ω 束缚态的光谱参数（ωe、ωexe、Be 和 αe）和平衡键长（Re）。这些结果与可用的实验数据非常吻合。