Struve W S
Ames Laboratory-USDOE, Iowa, USA.
Biophys J. 1995 Dec;69(6):2739-44. doi: 10.1016/S0006-3495(95)80145-1.
We describe Franck-Condon simulations of vibrational cooling effects on absorption difference spectra in chlorophyll a (Chl a). The relative contributions of vibrational equilibration in the electronic ground and excited states depend on the pump and probe wavelengths. For Franck-Condon-active vibrational modes exhibiting small Huang-Rhys factors (S < 0.1, characteristic in Chl a pigments), vibrational thermalization causes essentially no spectral changes when the origin band is excited. Significant spectral evolution does occur for S < 0.1 when the 0-1 and 1.0 (hot) vibronic bands are excited. However, vibrational equilibration in these cases causes no spectral shifting in the empirical photobleaching/stimulated emission band maximum. This result bears on the interpretation of time-resolved absorption difference spectra of Chl a-containing antennae such as the Chl a/b light-harvesting peripheral antenna of photosystem II.
我们描述了叶绿素a（Chl a）中振动冷却对吸收差异光谱影响的弗兰克-康登模拟。电子基态和激发态中振动平衡的相对贡献取决于泵浦光和探测光的波长。对于具有小黄-里斯因子（S < 0.1，Chl a色素的特征）的弗兰克-康登活性振动模式，当激发起源带时，振动热化基本上不会引起光谱变化。当激发0-1和1.0（热）振转带时，对于S < 0.1确实会发生显著的光谱演化。然而，在这些情况下，振动平衡在经验光漂白/受激发射带最大值处不会引起光谱移动。这一结果与含Chl a天线（如光系统II的Chl a/b捕光外周天线）的时间分辨吸收差异光谱的解释有关。
