Ross R T, Calvin M
Biophys J. 1967 Sep;7(5):595-614. doi: 10.1016/S0006-3495(67)86609-8.
A Planck law relationship between absorption and emission spectra is used to compute the fluorescence spectra of some photosynthetic systems from their absorption spectra. Calculated luminescence spectra of purple bacteria agree well but not perfectly with published experimental spectra. Application of the Planck law relation to published activation spectra for Systems I and II of spinach chloroplasts permits independent calculation of the luminescence spectra of the two systems; if the luminescence yield of System I is taken to be one-third the yield of System II, then the combined luminescence spectrum closely fits published experimental measurement.Consideration of the entropy associated with the excited state of the absorbing molecules is used to compute the oxidation-reduction potentials and maximum free-energy storage resulting from light absorption. Spinach chloroplasts under an illumination of 1 klux of white light can produce at most a potential difference of 1.32 ev for System I, and 1.36 ev for System II. In the absence of nonradiative losses, the maximum amount of free energy stored is 1.19 ev and 1.23 ev per photon absorbed for Systems I and II, respectively. The bacterium Chromatium under an illumination of 1 mw/cm(2) of Na D radiation can produce at most a potential difference of 0.90 ev; the maximum amount of free energy stored is 0.79 ev per photon absorbed.The combined effect of partial thermodynamic reversibility and a finite trapping rate on the amount of luminescence is considered briefly.
利用吸收光谱与发射光谱之间的普朗克定律关系，从一些光合系统的吸收光谱计算其荧光光谱。紫色细菌的计算发光光谱与已发表的实验光谱吻合良好，但并不完全一致。将普朗克定律关系应用于菠菜叶绿体系统I和系统II已发表的激活光谱，可以独立计算这两个系统的发光光谱；如果将系统I的发光产率设为系统II产率的三分之一，那么组合发光光谱与已发表的实验测量结果紧密拟合。考虑与吸收分子激发态相关的熵，用于计算光吸收产生的氧化还原电位和最大自由能存储量。在1千勒克斯白光照射下，菠菜叶绿体系统I最多可产生1.32电子伏特的电位差，系统II为1.36电子伏特。在不存在非辐射损失的情况下，系统I和系统II每吸收一个光子存储的最大自由能分别为1.19电子伏特和1.23电子伏特。在1毫瓦/平方厘米的钠D辐射照射下，嗜色菌最多可产生0.90电子伏特的电位差；每吸收一个光子存储的最大自由能为0.79电子伏特。简要考虑了部分热力学可逆性和有限俘获率对发光量的综合影响。
