Atsushi Ishizaki

Electronic Structures of Dyes and Phthalocyanines Estimated with “Photo-Electron Spectroscopy in Air (PESA)”

The near-edge electronic structures of several dyes and phtalocyanines were investigated using Photo-Electron Spectroscopy in Air (PESA). The ionization potentials (IPs) of N3, N719, Z907, D102, D149 and D205 were derived from observed photoemission threshold energies to be 5.88, 5.47, 5.44, 5.53, 5.44 and 5.49eV, respectively. Density of states (DOS) of Fe-, Ni-, Cu- and H2-phthalocyanines were deduced from differentiation of observed photoemission yields with incident photon energies. DOS thus obtained were well compared with calculated ones estimated with use of the DV-Xα molecular orbital calculation method.

Characterization of Catechins in Water by Photoemission Yield Spectroscopy in Air

Photoemission yield spectroscopy in air (PYSA) was applied for the characterization of catechins in water in ambient conditions. According to the results of measurements on aqueous solutions of epigallocatechin gallate (EGCg) of various concentrations, the photoemission yield is almost proportional to the concentration of EGCg. Contrarily, the threshold energy of photoemission, EPET, is almost constant at 5.46 ± 0.02 eV. Moreover, we measured aqueous solutions of epicatechin (EC), epigallocatechin (EGC), and epicatechin gallate (ECg). The values of EPET of EC, EGC, ECg were estimated to be 5.72 ± 0.02, 5.68 ± 0.01, and 5.45 ± 0.02 eV, respectively, and a dependence on the molecular structure was found. Furthermore, changes in the photoemission yield spectra of heated EGCg were well explained by molecular orbital calculations on the basis of an assumption of epimerization.