High-resolution synchrotron FTIR spectroscopic analysis of the Coriolis interaction between the <i>v</i>₁₀ = 1 and <i>v</i>₈ = 1 states of ethylene-<i>cis</i>-1,2-<i>d</i>₂

The synchrotron Fourier transform infrared (FTIR) spectrum of the <i>b</i>-type ν₁₀ band of ethylene-<i>cis</i>-1,2<i>-d</i>₂ (<i>cis</i>-C₂H₂D₂) was recorded at a resolution of 0.00096 cm⁻¹ in the 550–750 cm⁻¹ region. The measured FWHM of the lines was about 0.002 cm⁻¹. The ν₁₀ band, centred at 662.871885(27) cm⁻¹ was found to be perturbed through a <i>b-</i>type Coriolis resonance with the infrared inactive ν₈ at 759.9582(20) cm⁻¹. In this work, 1989 infrared transitions of ν₁₀ were assigned for the first time. These perturbed and unperturbed infrared transitions were fitted with an rms deviation of 0.00033 cm⁻¹ using the Watson's <i>A</i>-reduced Hamiltonian in the <i>I^r</i> representation with three Coriolis terms to derive the rovibrational constants for <i>v</i>₁₀ = 1 and <i>v</i>₈ = 1 states. Ground state rovibrational constants up to two sextic terms were also derived from a fit of a total of 2532 ground state combination differences with arms deviation of 0.00030 cm⁻¹ from the infrared transitions of the present analysis and those determined previously. The ground state constants compared favourably to the equilibrium state constants from harmonic cc-pVTZ basis set at CCSD(T), MP2 and B3LYP levels. The rotational constants of ν₁₀ and ν₈ from this work agree well with those from anharmonic calculations.本研究记录了顺式-1,2-二氘代乙烯（cis-C₂H₂D₂）的b型ν₁₀振动带的同步辐射傅里叶变换红外（FTIR）光谱，光谱分辨率为0.00096 cm⁻¹，测量波数范围覆盖550~750 cm⁻¹。测得的谱线半高全宽（FWHM）约为0.002 cm⁻¹。中心波数为662.871885(27) cm⁻¹的ν₁₀振动带，被发现与波数759.9582(20) cm⁻¹的红外非活性振动带ν₈发生b型科里奥利共振（Coriolis resonance）相互作用，从而产生微扰。本研究首次归属了ν₁₀振动带的1989条红外跃迁谱线。本研究采用Watson的Iᵣ表象下的A约化哈密顿量（Hamiltonian），结合三项科里奥利项对上述受扰与未受扰的红外跃迁谱线进行拟合，拟合均方根偏差（rms deviation）为0.00033 cm⁻¹，由此得到v₁₀=1与v₈=1振动能级的振转常数（rovibrational constants）。本研究还通过拟合共计2532条基态组合差（ground state combination differences）数据，得到了最高至两项六次项（sextic terms）的基态振转常数；该拟合基于本研究的红外跃迁数据与已发表的相关跃迁数据，整体均方根偏差为0.00030 cm⁻¹。本研究得到的基态常数，与在CCSD(T)、MP2及B3LYP理论水平下，采用cc-pVTZ基组计算得到的平衡态常数吻合良好。本研究得到的ν₁₀与ν₈振动带的转动常数，与非谐性计算结果吻合良好。

搜集汇总

背景与挑战

背景概述

该数据集包含乙烯-cis-1,2-d2在550–750 cm−1区域的高分辨率同步辐射FTIR光谱数据，分辨率为0.00096 cm−1，重点分析了v10和v8状态之间的科里奥利相互作用。数据集提供了1989个首次分配的红外跃迁数据，并通过Watson's A-reduced Hamiltonian拟合，推导了振动-转动常数，适用于分子光谱学和物理化学研究。