A Dynamic Coupling Model for Sum Frequency Chiral Response from Liquids Composed of Molecules with a Chiral Side Chain and an Achiral Chromophore

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• 作者：Na Ji and Yuen-Ron Shen
• 刊名：Journal of the American Chemical Society
• 出版年：2005
• 出版时间：September 21, 2005
• 年：2005
• 卷：127
• 期：37
• 页码：12933 - 12942
• 全文大小：266K
• 年卷期：v.127,no.37(September 21, 2005)
• ISSN：1520-5126

文摘

A theoretical formulation for optically active sum frequency generation (OA-SFG) from isotropicchiral solutions was proposed for molecules with a chiral side chain and an intrinsically achiral chromophore.Adapting an electron correlation model first proposed by Höhn and Weigang for linear optical activity, wepresented a dynamic coupling model for OA-SFG near the electronic resonance of the achiral chromophore.As a demonstration, we used this model to explain the observed OA-SFG spectra of a series of aminoacids near the electronic resonance of the intrinsically achiral carboxyl group. Our model shows that thenonlinear chiroptical response comes about by the through-space correlative electronic interactions betweenthe chiral side chain and the achiral chromophore, and its magnitude is determined by the position andorientation of the bonds that make up the chiral side chain. Using the bond polarizability values in theliterature and the conformations of amino acids obtained from calculation, we were able to reproduce therelative OA-SFG strength from a series of amino acids.