Subject：Computational spectroscopy–as applied in photophysics, photochemistry, and material science
Speaker：Prof. Weijie Hua
Emcee：Prof. Konstantin Dorfman
Time：10:00am, 24th Sept, 2019
Place：Optics Building A214
Abstract：
Spectroscopy uses light-matter interaction to probe the structures of molecules and materials. Spectral simulation at the quantum mechanical level can help make reliable interpretations of experimental features, which guarantees correct further analysis to extract the underlying physical insights. In this talk, I will present our recent computational spectroscopy studies in the optical and X-ray regime, in order to elucidate the photophysical/photochemical mechanisms and the structure-spectroscopy relation. With QM/MM approach and time-dependent density functional theory, we simulated UV absorption, and vibrationally-resolved fluorescence and phosphorescence spectra for donor-acceptor molecular co-crystals to help investigate the details of thermally-activated delayed fluorescence (TADF) photophysics. At the multiconfigurational quantum chemistry level, transient X-ray absorption spectroscopy (TXAS) of the isolated uracil molecule was simulated to help identify the photo-decay mechanisms from the ππ* state (S2) and spectral fingerprints of the nπ* dark state (S1). With density functional theory, X-ray photoelectron and absorption spectroscopy of 2D materials (N-doped graphdyine and g-C3N4) was simulated to determine the local structures and make correct spectroscopic interpretations. Good agreement with experiment was achieved in all cases, and we discuss to employ appropriate computational methods for different problems so as to best bridge experiment and theory.
