Abstract: The structures of the Au(I) complexes were fully optimized by using the MP2 method for the ground states and the CIS method for the excited states. In the ground states, it is clear that the molecule distances show a tendency of shortening towards middle; the modification effect of Au(I) weakens the bonding inside the ligand; with the lengthening of molecules, the bonding between the metal and ligand is weakened. In the excited states, the bonding effect between metal and ligand is weakened because of the electron transitions, which becomes clear with the lengthening of molecules. The results showed that the fluorescences of the Au(I) complexes have an inimitable nature, and the —AuPH3 has more ionic nature than —H.

Key words: [Au(PH3)]+, Excited state, Theoretical study, Fluorescence