Detailed study of pyridine at the C 1s and N 1s ionization thresholds: The influence of the vibrational fine structure

• DOI: 10.1063/1.1397797
• Publication Date: 2002-07-26T12:45:28Z
• Authors: C. Kolczewski; R. Püttner; O. Plashkevych; H. Ågren; V. Staemmler; M. Martins; G. Snell; A. S. Schlachter; M. Sant’Anna; G. Kaindl; L. G. M. Pettersson
• Keywords: Vibronic coupling; Vibrational energy relaxation

High resolution, vibrationally resolved, near-edge x-ray absorption fine structure (NEXAFS) spectra at the C 1s and N ionization thresholds of pyridine deuterated d5-pyridine in gas phase have been recorded. The high resolution 65 meV (150 meV) s (N 1s) reveals vibrational structures spectra. Detailed ab initio density functional theory (DFT) calculations were performed to interpret experimental assign observed peaks. In particular we focused on previously unexplained intensity ratio for two components 1s→1π* transition. For this transition is included through a linear coupling model DFT leads experimentally ∼2:3 between π* spectrum rather than ∼3:2 obtained without effects. After inclusion relaxation effects excited states, addition effects, both theoretical methods yield almost perfect agreement with experiment.