1. Vibrationally resolved high-resolution NEXAFS and XPS spectra of phenanthrene and coronene
- Author
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Fronzoni, Giovanna, Baseggio, Oscar, Stener, Mauro, Hua, Weijie, Tian, Guangjun, Luo, Yi, Apicella, Barbara, Alfe, Michela, de Simone, Monica, Kivimäki, Antti, Coreno, Marcello, Fronzoni, Giovanna, Baseggio, Oscar, Stener, Mauro, Hua, Weijie, Tian, Guangjun, Luo, Yi, Apicella, Barbara, Alfe, Michela, de Simone, Monica, Kivimäki, Antti, and Coreno, Marcello
- Abstract
We performed a combined experimental and theoretical study of the C1s Near-Edge X-ray Absorption Fine-Structure (NEXAFS) spectroscopy and X-ray Photoelectron Spectroscopy in the gas phase of two polycyclic aromatic hydrocarbons (phenanthrene and coronene), typically formed in combustion reactions. In the NEXAFS of both molecules, a double-peak structure appears in the C1s -> LUMO region, which differ by less than 1 eV in transition energies. The vibronic coupling is found to play an important role in such systems. It leads to weakening of the lower-energy peak and strengthening of the higher-energy one because the 0 - n (n > 0) vibrational progressions of the lower-energy peak appear in nearly the same region of the higher-energy peak. Vibrationally resolved theoretical spectra computed within the Frank-Condon (FC) approximation and linear coupling model agree well with the high-resolution experimental results. We find that FC-active normal modes all correspond to in-plane vibrations., QC 20140919
- Published
- 2014
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