Abstract: The excited state wave function of chiral enantiomer of S-methionine (S-Met) under implicit solvent was calculated, and the percentage of charge transfer between fragments was calculated based on the atomic charge. The results show that the atomic dipole moment corrected Hirshfeld (ADCH) and Hirshfeld charge methods have the same qualitative results, and the quantitative results are quite different. The calculated results of the charge transfer of S-Met molecular system fragment are basically the same under the implicit solvent H₂O and methanol, and the changes of Mayer bondlevel between the fragments and the other parts of the molecule are basically the same.

Key words: methionine, atomic charge, charge transfer, orbital fragment