Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, Florida 32611, USA.
J Chem Phys. 2023 Jan 28;158(4):044301. doi: 10.1063/5.0137340.
In this work, we present the spectral analysis of 1H- and 2H-1,2,3-triazole vibrationally excited states alongside provisional and practical computational predictions of the excited-state quartic centrifugal distortion constants. The low-energy fundamental vibrational states of 1H-1,2,3-triazole and five of its deuteriated isotopologues ([1-H]-, [4-H]-, [5-H]-, [4,5-H]-, and [1,4,5-H]-1H-1,2,3-triazole), as well as those of 2H-1,2,3-triazole and five of its deuteriated isotopologues ([2-H]-, [4-H]-, [2,4-H]-, [4,5-H]-, and [2,4,5-H]-2H-1,2,3-triazole), are studied using millimeter-wave spectroscopy in the 130-375 GHz frequency region. The normal and [2-H]-isotopologues of 2H-1,2,3-triazole are also analyzed using high-resolution infrared spectroscopy, determining the precise energies of three of their low-energy fundamental states. The resulting spectroscopic constants for each of the vibrationally excited states are reported for the first time. Coupled-cluster vibration-rotation interaction constants are compared with each of their experimentally determined values, often showing agreement within 500 kHz. Newly available coupled-cluster predictions of the excited-state quartic centrifugal distortion constants based on fourth-order vibrational perturbation theory are benchmarked using a large number of the 1,2,3-triazole tautomer isotopologues and vibrationally excited states studied.
在这项工作中，我们展示了 1H-和 2H-1,2,3-三唑振动激发态的光谱分析，以及激发态四次离心畸变常数的暂定和实际计算预测。1H-1,2,3-三唑及其五种氘代同位素（[1-H]-，[4-H]-，[5-H]-，[4,5-H]-和[1,4,5-H]-1H-1,2,3-三唑）以及 2H-1,2,3-三唑及其五种氘代同位素（[2-H]-，[4-H]-，[2,4-H]-，[4,5-H]-和[2,4,5-H]-2H-1,2,3-三唑）的低能基本振动态，使用毫米波光谱学在 130-375GHz 频率范围内进行研究。使用高分辨率红外光谱分析了正常和[2-H]-同位素的 2H-1,2,3-三唑，确定了它们三个低能基本态的精确能量。每个振动激发态的光谱常数均为首次报道。偶极-偶极相互作用常数与各自的实验值进行了比较，通常在 500kHz 以内具有一致性。基于四阶振动微扰理论的新的可用激发态四次离心畸变常数的耦合簇预测，使用大量 1,2,3-三唑互变异构体同位素和振动激发态进行了基准测试。
