Single site electronic spectroscopy of zinc and magnesium chlorin in n-octane matrixes at 7 K

The high resolution, single site fluorescence and absorption spectra of zin c and magnesium chlorin in n-octane matrixes at 7 K are reported. Both the Q and Soret band regions have been investigated; The vibrational frequencie s of the ground and four lowest energy pi pi* singlet excited states were d etermined from fluorescence and excitation spectra, respectively. The fluor escence and Q(y) region spectra are similar, having intense, narrow origin bands followed by relatively weak but orderly vibrational structure. The Q( x) regions of these two metal chlorins do not have clear origins and exhibi t complex vibrational structure which increases in intensity going to highe r energy. In the Soret regions, the individual pi pi* origins are clearly i dentifiable and some Vibrational structure is also observed.