Development of inter-molecular interaction theory for excited states

根据分子环境的不同，一些光功能蛋白(人眼视锥色素和荧光蛋白)会显著改变其光吸收/发射能量。我们进行了量子化学计算来分析这一机制。我们发现，在激发时，生色团的电荷分布发生了显著的变化，蛋白质产生了极化的静电势。这两个因素对激发能有协同作用。我们还发现，靠近发色团的氨基酸的波函数也影响一些视网膜蛋白质的激发能。为了分析蛋白质环境的电子效应，我们开发了一种新的定位方案，可以将MO定位到预定的形状和区域。应用这种局部化方案分析了激励传递的途径。

Depending on molecular environment, some photo-functional proteins(human visual cone pigments and fluorescent proteins) significantly change their photo-absorption/emission energy. We performed quantum chemical calculations to analyze the mechanism. We found that, upon excitation, the charge distributions of the chromophores change significantly and the proteins produce polarized electrostatic potential. These two facts cause a synergy effect on the excitation energy. We also found that the wave functions of amino acids close to the chromophore also affect the excitation energy in some retinal proteins. To analyze the electronic effect of the protein environment, we have developed a new localization scheme that can localize MOs into predefined shapes and regions. This localization scheme was applied to analyze the pathway for the excitation transfer.