The influence of the structure of the radical cation dimer pair of aromatic molecules on the principal values of a g-tensor: DFT predictions

The density functional theory calculations were carried out to determine the influence of the structure of the radical cation dimer pair of model aromatic molecules on the principal values of a g-tensor. The calculated results for different model structures of (naphthalene)2 and (p-dimethylenebenzene)2 and individual model naphthalene and p-dimethylenebenzene molecules were analyzed by comparing results of calculations for different models. This comparison predicts an analogous effect for g-tensor principal values of P 700 + special dimer pair radical cation in core Photosystem I and for g-tensor principal values of the P 700 T special dimer pair triplet radical in core Photosystem I. The change in the g-tensor principal values in stacked structures of p-terphenyl cation radical was deduced from an extended model stacked multimer structure.