在低温的状态下, 类球红细菌内天然叶绿素的反应中心发生的电荷分离对激发波长有较弱的依赖性, 而这种依赖可能来源于分子内电荷转移态。我们采用表现出更多的电荷转移态性质的突变叶绿素为反应中心, 对这种电荷分离过程中的激发波长依赖和温度依赖的性质做了进一步的研究。研究发现:突变的异质二聚体存在的两种激发态(定域的激发态与分子内电荷转移态)是相互强耦合的, 在突变的分子异质二聚体中形成的电荷转移态并不是电荷分离的有效途径。随着温度的降低, 异质二聚体的活性降低, 从而电荷分离产率下降。

At low temperature, primary charge separation in reaction centers of wild type rhodobacter sphaeroides show weak excitation wavelength dependence. It comes from the existence of the intramolecular charge transfer state. Herein, we find such kind of heterodimer mutant has more intramolecular charge transfer character and its excitation wavelength depend on temperature. The results show the excited state of heterodimer has two states (local and charge transfer) and they are strong coupling; Intramolecular charge transfer state is not favor to charge separation, as temperature decrease it becomes dark and charge separation yield decrease.