COMPUTATIONAL ANALYSIS OF THE FIRST STAGE OF THE PHOTOSYNTHETIC SYSTEM, THE LIGHT-DEPENDENT REACTION, BY QUANTUM CHEMICAL SIMULATION METHOD

摘要

Calculation was done about the optimized geometries of special pair consisting of "bacteriochlorophyll a" based on the PDB structural data (3zuw) by quantum simulation method. The quantum chemical calculation for the optimized geometries exhibited the electronic excitation transition with large oscillator strength at 860 nm, characterizing P870. Therefore, the optimized geometries were reasonably assigned to a model of real P870. The geometries of cationic dimer were also optimized by the above method. The charge separation process upon photo-excitation was concluded to be impossible by considering the difference between the heat of formation of the neutral and cation dimers and the ionization energy of the neutral dimer.