The hematoporphyrin have several isomers. These isomers often exist in two types

alternate substitute and non-symmetry substitute.At the room temperature

the spectra of the hematoporphyrin in solution have the character of broad band

which have no vibronic structure and can not give the feature of the different isomers.Using the flashlamp pumped tunable Rh 6G dye laser

we was made the selective excitation for the electronic-vibronic levels of the hematoporphyrin in the ethanal at 77K. In experiment

the laser linewidth taken is lager than the homogeneous linewidth and narrower than the inhomogeneous linewidth

in order to distinguish the different feature of the isomer. The results show that four narrowed peaks appear in the region of 0-0 transition for different excitative wavelength. It is possible that these peaks belong to isomer molecules with the electronic vibranica transition frequency as consistent with the laser excitative freguency. Since the vibronic levels of the different molecules superposed each other

several peaks simultaneously was observed in the region of the 0-0 transition. The position of different 0-0 transition peaks are relatively shifted from difference of the structure symmetry. Two peaks appeared in the fluorescence spectra at 77K belong to two main kinds of the isomer.In (1N) HCl solution

since the structural symetry increased the fluorescent spectra occured blue-shift. Thus 0-0 transition band lies on the region of 570-600nm

which just consistent with the tunable range of the Rh 6G dye laser. The structural fluorescent spectra are occured by laser selective excitation in the region of 0-0 transition. When excitation at λ=591.3nm the vibronic structure is clear but as the excitative wavelength shortened the structure disappears stepwise. This phenomenon can. be interpret as overlaping of the pure electronic transition with the phonon sideband in the shorter wavelength side of the 0-phonon line. The experimental results indicated that the electronic-phonon coupling of the HPD in these solvent is not very strong.