Multidimensional infrared spectroscopy for molecular vibrational modes with dipolar interactions, anharmonicity, and nonlinearity of dipole moments and polarizability.
Multidimensional infrared spectroscopy for molecular vibrational modes with dipolar interactions, anharmonicity, and nonlinearity of dipole moments and polarizability.
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DOI：
10.1063/1.2134702
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发表时间：
2005-12
期刊：
影响因子：
--
通讯作者：
K. Hyeon‐Deuk;Y. Tanimura
中科院分区：
文献类型：
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作者：
K. Hyeon‐Deuk;Y. Tanimura
我们提出了一个相互作用分子振动运动的线性和非线性红外光谱的解析表达式。每个分子模式明确表示为一个经典的阻尼振子的非谐多维势能面。两个基本的相互作用，偶极-偶极（DD）和偶极-诱导-偶极（DID）的相互作用，被考虑在内，和每个偶极矩和极化率展开到相对于核振动坐标的非线性顺序。我们的分析处理导致表达式的非谐性，DD和DID相互作用的贡献，和非线性的偶极矩和极化率元素的一维，二维和三维光谱作为单独的条款，这使我们能够讨论这些各自的贡献的相对重要性。我们可以计算多维信号的各种配置的分子通过DD和DID相互作用的不同材料参数在整个频率范围内的相互作用。我们证明，DD和DID相互作用和非谐性的贡献是分别通过三阶三维红外光谱检测，而它们不能区分彼此的线性或二阶红外光谱。本文还讨论了从多维光谱中获得分子内或分子间结构信息的可能性。
We present an analytical expression for the linear and nonlinear infrared spectra of interacting molecular vibrational motions. Each of the molecular modes is explicitly represented by a classical damped oscillator on an anharmonic multidimensional potential-energy surface. The two essential interactions, the dipole-dipole (DD) and the dipole-induced-dipole (DID) interactions, are taken into account, and each dipole moment and polarizability are expanded to nonlinear order with respect to the nuclear vibrational coordinate. Our analytical treatment leads to expressions for the contributions of anharmonicity, DD and DID interactions, and the nonlinearity of dipole moments and polarizability elements to the one-, two-, and three-dimensional spectra as separated terms, which allows us to discuss the relative importance of these respective contributions. We can calculate multidimensional signals for various configurations of molecules interacting through DD and DID interactions for different material parameters over the whole range of frequencies. We demonstrate that contributions from the DD and DID interactions and anharmonicity are separately detectable through the third-order three-dimensional IR spectroscopy, whereas they cannot be distinguished from each other in either the linear or the second-order IR spectroscopies. The possibility of obtaining the intra- or intermolecular structural information from multidimensional spectra is also discussed.