The rotational spectrum of the deuterated isopropanol (CH(3))(2)CHOD has been observed by Fourier transform microwave spectroscopy and analyzed to yield tunneling splitting of 4431.4613 (17) MHz, between the antisymmetric and the symmetric gauche forms, which is much larger than the 2400 MHz estimated from the internal-rotation potential function reported in the literature. The potential function for the OH internal rotation has been examined in view of the discrepancy between the observed and estimated tunneling splitting, and it was accounted for by taking into account isotope effects on the potential constants. The deuterium quadrupole coupling effect has been included together with the Coriolis terms in the off-diagonal block of the Hamiltonian matrix for the gauche form. The deuterium quadrupole coupling constants obtained for the trans form were employed to calculate the components of the coupling constants as functions of the internal-rotation angle, and the components at around 120 degrees were compared with the values observed for the gauche form, thereby leading to unambiguous determination of the signs of the constants in the off-diagonal block; the signs are not obtainable from an ordinary analysis of the rotational spectra. The chirality of the gauche form was discussed by placing special emphasis on the effect of intermolecular interactions between two chiral molecules. Copyright 2001 Academic Press.

中文翻译：

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异丙醇中羟基的内旋和 Gauche 形式的手性：(CH3)2CHOD 的傅立叶变换微波光谱

氘代异丙醇 (CH(3))(2)CHOD 的旋转光谱已通过傅立叶变换微波光谱观察到并分析产生 4431.4613 (17) MHz 的隧道分裂，在反对称和对称 gauche 形式之间，这是很多大于根据文献中报道的内旋转势函数估计的 2400 MHz。鉴于观察到的和估计的隧穿分裂之间的差异，已经检查了 OH 内旋的势函数，并通过考虑同位素对势常数的影响来解释。氘四极耦合效应与科里奥利项一起包含在 gauche 形式的哈密顿矩阵的非对角块中。使用为变换形式获得的氘四极耦合常数来计算作为内旋转角函数的耦合常数分量，并将大约 120 度处的分量与对焦西形式观察到的值进行比较，从而导致明确确定非对角块中常数的符号；这些符号无法从旋转光谱的普通分析中获得。通过特别强调两个手性分子之间的分子间相互作用的影响，讨论了 gauche 形式的手性。版权所有 2001 学术出版社。将大约 120 度的分量与观察到的 gauche 形式的值进行比较，从而明确确定非对角块中常数的符号；这些符号无法从旋转光谱的普通分析中获得。通过特别强调两个手性分子之间的分子间相互作用的影响，讨论了 gauche 形式的手性。版权所有 2001 学术出版社。将大约 120 度的分量与观察到的 gauche 形式的值进行比较，从而明确确定非对角块中常数的符号；这些符号无法从旋转光谱的普通分析中获得。通过特别强调两个手性分子之间的分子间相互作用的影响，讨论了 gauche 形式的手性。版权所有 2001 学术出版社。