Simulation of NEXAFS spectra of a photo-reactive copolymer with considerably large monomer units: An ab initio molecular orbital study

We performed the simulation of near edge X-ray absorption fine structure (NEXAFS) spectra of a photo-reactive copolymer with considerably large monomer units by ab initio molecular orbital calculation, in order to explain the spectral change induced by irradiation of the linearly polarized near ultra-violet (LPNUV) light. The “building block approach” is applied for the theoretical calculation to calculate the core-excited states of the polymer with such large monomer units; the monomer unit is divided into subunits, whose core-excited states are calculated individually, and the results are summed up to simulate the spectra of the polymer. With the result of the simulation, the peaks in the observed spectra were assigned. The spectral change after the LPNUV-irradiation is attributed to the change in the electronic structure caused by the breakdown of the π-conjugation system of chalconyl group after photo-dimerization.