Spectroscopic investigation of various transition metal complexes was made by use of absorption spectroscopy and multiphoton ionization. Low temperature absorption spectra of Re4+ ion in distorted substitutional sites in (NR4)2SnCl6 (R = CH3, C2H5, and C3H7) hosts have been measured. The effects of reduced host symmetry have been observed such as increasing origin intensity, origin shift, different vibronic pattern. In addition, several new transitions located at above 16,000 cm-1 have been found. The experimental results and calculational efforts on the newly observed "extra" bands of Re4+ in the (NR4)2SnCl6 host crystals indicated that these transitions can not be fit very well. Ligand field theory might be limited to explain these "extra" transitional bands.
The next part of this research involved the MPI of various transition metal complexes in a pulsed supersonic jet expansion. Several instrumental modifications have been made. The multiphoton dissociation and ionization have been observed in Ni(CO)4, nickelocene, and cobalt complexes, which gave us valuable information such as dissociation dynamics and intra molecular energy transfer. Finally, molecular MPI spectra of WF6 have been measured. Clear assignments on molecular MPI bands of WF6 could not be made at present status.