Quantum tunneling in the midrange vibrational fundamentals of tropolone.
Quantum tunneling in the midrange vibrational fundamentals of tropolone.
复制标题
托酚酮中频振动基础的量子隧道效应。
DOI：
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发表时间：
2006
影响因子：
2.9
通讯作者：
R. Sams
中科院分区：
文献类型：
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作者：
R. L. Redington;T. Redington;R. Sams
托酚酮(OH)蒸气在1175-1700 cm(-1) 区域的傅里叶变换红外光谱报告的光谱分辨率为0.0025 和0.10 cm(-1)。在这个振动态密度快速上升的区域中，12 个振动基本原理由 CC、CO、CCH 和 COH 内坐标的混合主导。报告了 11 个光谱双峰分量分离 DS(v) = |Delta(v) +/- Delta(0)| 的基于尖锐 Q 分支峰测量的估计值。 Delta(0) = 0.974 cm(-1) 是已知的零点分裂，三个 a(1) 模式显示隧道分裂 Delta(v) 约为 Delta(0)，四个 b(2) 模式显示分裂 Delta(v) 约为 0.90Delta(0)，其余四种模式显示分裂 Delta(v) 从 Delta(0) 下降 5-14%。 COH弯曲模式nu(8)(a(1))很小，即距Delta(0)的10%。许多振动激发态表现出强烈的非谐行为，但驱动 Delta(0) 的互变异构机制仅存在轻微的扰动。数据表明，特别是对于较高频率的 a(1) 基本原理，选择性分子内振动能量重新分布过程的开始在互变异构过程的时间尺度上是快速的。这些似乎使零点势能表面的形貌变化离域化并平滑，预计这些变化会随着 nu(v) 光子的吸收而发生。此外，频谱显示了 b(2) 的 Delta(v) 分裂和其他复杂振动相对于 Delta(0) 被阻尼的倾向。
The Fourier transform infrared spectrum of tropolone(OH) vapor in the 1175-1700 cm(-1) region is reported at 0.0025 and 0.10 cm(-1) spectral resolutions. The 12 vibrational fundamentals in this region of rapidly rising vibrational state density are dominated by mixtures of the CC, CO, CCH, and COH internal coordinates. Estimates based on the measurement of sharp Q branch peaks are reported for 11 of the spectral doublet component separations DS(v) = |Delta(v) +/- Delta(0)|. Delta(0) = 0.974 cm(-1) is the known zero-point splitting, and three a(1) modes show tunneling splittings Delta(v) approximately Delta(0), four b(2) modes show splittings Delta(v) approximately 0.90Delta(0), and the remaining four modes show splittings Delta(v) falling 5-14% from Delta(0.) Significantly, the splitting for the nominal COH bending mode nu(8) (a(1)) is small, that is, 10% from Delta(0). Many of the vibrational excited states demonstrate strong anharmonic behavior, but there are only mild perturbations on the tautomerization mechanism driving Delta(0). The data suggest, especially for the higher frequency a(1) fundamentals, the onset of selective intramolecular vibrational energy redistribution processes that are fast on the time scale of the tautomerization process. These appear to delocalize and smooth out the topographical modifications of the zero-point potential energy surface that are anticipated to follow absorption of the nu(v) photon. Further, the spectra show the propensity for the Delta(v) splittings of b(2) and other complex vibrations to be damped relative to Delta(0).