Ground-state, excited-singlet-state, and excited-triplet-state energy levels and photophysics of the three rotational isomers of isophthalaldehyde vapor.
Emission, excitation, and absorption spectra of isophthalaldehyde (benzene-1,3-dicarboxaldehyde) vapor have been measured at different temperatures, along with the UV-vis and IR absorption spectra in solution. Analyses of the temperature dependence of the phosphorescence and excitation spectra of isophthalaldehyde vapor revealed the energetic relationships among the three rotational isomers in the T1(n, pi*), S1(n, pi*), and ground states. This appears to be the first example of the system where the S0, T1, and S1 energy levels are determined for the three rotational isomers. The phosphorescence, fluorescence, and excitation origins of the three rotamers were assigned on the basis of the results of the density functional theory (DFT) and semiempirical SCF-MO calculations and infrared data as well as on the basis of the temperature dependence of the emission and excitation spectra.
Graduate School of Integrated Arts and Sciences, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima City 739-8521, Japan. titoh@hiroshima-u.ac.jp
Takao
T
Itoh