Abstract
The experimental near-edge x-ray-absorption fine-structure spectrum of the benzonitrile molecule in the gas phase shows well separated double peaks with different vibrational profiles. Hybrid density-functional theory calculations reveal that such a separation is a result of the conjugation effect on the nitrogen orbitals and the double spectral peaks can be assigned as the out-of-plane and in-plane resonances. The vibrational profiles have been analyzed using a combined transition state theory and linear coupling model. Each profile consists of two different vibrational progressions corresponding to stretching modes and a broad continuum of bending excited states. The use of transition state theory allows identifying the dynamics of the N core excitation. It is found that upon core excitations the bond of the benzonitrile molecule can go from initial linear to final bent structures through different paths. The calculated spectrum is in excellent agreement with experiment.
4 More- Received 23 September 2004
DOI:https://doi.org/10.1103/PhysRevA.71.022511
©2005 American Physical Society