Theoretical Insights into Intermolecular Hydrogen-Bonding Strengthening in Fluorenone-Methanol Complexes Induced by Electronic Excitation and Bulk Solvent Effect  

作　　者：Chao Sun 

机构地区：[1]State Key Laboratory of Physical Chemistry of Solid Surfaces, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China [2]Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230026, China

出　　处：《Chinese Journal of Chemical Physics》2013年第6期617-626,I0003,共11页化学物理学报（英文）

摘　　要：This work presents a theoretical insight into the variation of the site-specific intermolecular hydrogen-bonding （HB）, formed between C=O group of fluorenone （FN） and O-H groups of methanol （MeOL） molecules, induced by both the electronic excitation and the bulk solvent effect. Through the calculation of molecular ground- and excited-state properties, we not only demonstrate the characters of HB strengthening induced by electronic excitation and the bulk solvent effect but also reveal the underlying physical mechanism which leads to the HB variation. The strengthening of the intermolecular HB in electronically excited states and in liquid solution is characterized by the reduced HB bond-lengths and the red-shift IR spectra accompanied by the increasing intensities of IR absorption corresponding to the characteristic vibrational modes of the O-H and C--O stretching. The HB strengthening in the excited electronic states and in solution mainly arises from the charge redistribution of the FN molecule induced by the electronic excitation and bulk solvent instead of the intermolecular charge transfer. The charge redistribution of the solute molecule increases the partial dipole moment of FN molecule and the FN-MeOL intermolecular interaction, which subsequently leads to the HB strengthening. With the bulk solvent effect getting involved, the theoretical IR spectra of HBed FN-MeOL complexes agree much better with the experiments than those of gas-phase FN-MeOL dimer. All the calculations are carried out based on our developed analytical approaches for the first and second energy derivatives of excited electronic state within the time-dependent density functional theory.

关 键 词：Time-dependent density functional theory Excited-state property Hydrogen bond Intermolecular interaction 

分 类 号：O753.2[理学—晶体学] O561.4