Ultrafast carotenoid band shifts:: Experiment and theory
Ultrafast carotenoid band shifts:: Experiment and theory
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DOI：
10.1021/jp040094p
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发表时间：
2004-07-22
影响因子：
3.3
通讯作者：
Pullerits, T
中科院分区：
文献类型：
--
作者：
Herek, JL;Wendling, M;Pullerits, T
在紫色细菌的三种不同的光收获配合物中，研究了附近细菌叶绿素分子激发的超快类胡萝卜素带位移。从类胡萝卜素局部电场变化的角度对结果进行了分析。基于已知结构和模型结构的时间依赖密度泛函理论计算与实验结果很好地吻合，强烈表明色素分子的相互取向而不是类胡萝卜素分子的类型决定了超快带位移的程度。我们进一步估计，蛋白质诱导的类胡萝卜素分子附近的局部场约为4或6 MV/cm，这取决于类胡萝卜素在光学跃迁时电偶极子变化的方向。
The ultrafast carotenoid band shift upon excitation of nearby bacteriochlorophyll molecules was studied in three different light harvesting complexes from purple bacteria. The results were analyzed in terms of changes in local electric field of the carotenoids. Time dependent density functional theory calculations based on known and model structures led to good agreement with experimental results, strongly suggesting that the mutual orientation of the pigment molecules rather than the type of the carotenoid molecules determines the extent of the ultrafast band shift. We further estimate that the protein induced local field nearby carotenoid molecule is about 4 or 6 MV/cm, depending on the orientation of the change of the electrical dipole in the carotenoid upon optical transition.