Dalagnol Luiz V S, Kumar Sarvesh, Barbosa Alessandra S, Akther Umma S, Jones Nykola C, Hoffmann Søren V, Bettega Márcio H F, Limão-Vieira Paulo
Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, Curitiba 81531-980, Paraná, Brazil.
Atomic and Molecular Collisions Laboratory, CEFITEC-Centre of Physics and Technological Research, Department of Physics, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
Molecules. 2024 Nov 27;29(23):5619. doi: 10.3390/molecules29235619.
We report absolute high-resolution vacuum ultraviolet (VUV) photoabsorption cross-sections of carbon tetrachloride (CCl) in the photon energy range 5.0-10.8 eV (248-115 nm). The molecular spectrum and electronic structure have been comprehensively investigated together with quantum chemical calculations, providing geometries, bond lengths, vertical excitation energies and oscillator strengths. The major electronic excitations have been assigned to valence and Rydberg transitions which are also accompanied by vibrational excitation assigned to degenerate stretching, v3't2 and degenerate deformation v4't2 modes. The rather complex nuclear dynamics along the degenerate deformation mode, v4't2, have been thoroughly investigated by Time-Dependent Density Functional Theory (TD-DFT) method. The relevant Jahn-Teller distortion operative within the lowest-lying electronic excited-state is shown here for the first time in order to yield a weak absorption feature at 6.156 eV. Further calculations on the potential energy curves for the singlet excited-states along the C-Cl stretching coordinate show the relevance of efficient C-Cl bond excision.
我们报告了四氯化碳（CCl₄）在5.0 - 10.8电子伏特（248 - 115纳米）光子能量范围内的绝对高分辨率真空紫外（VUV）光吸收截面。结合量子化学计算对分子光谱和电子结构进行了全面研究，给出了几何结构、键长、垂直激发能和振子强度。主要的电子激发已被归因于价电子跃迁和里德堡跃迁，同时还伴随着归属于简并伸缩振动v₃'t₂和简并变形振动v₄'t₂模式的振动激发。通过含时密度泛函理论（TD - DFT）方法对沿简并变形模式v₄'t₂的相当复杂的核动力学进行了深入研究。首次展示了在最低电子激发态中起作用的相关 Jahn - Teller 畸变，以便在6.156电子伏特处产生一个弱吸收特征。沿着C - Cl伸缩坐标对单重激发态的势能曲线进行的进一步计算表明了有效C - Cl键切除的相关性。
