Vibronic coupling of pyridine in the nπ* excited state

Abstract
The electronic absorption spectra and Raman spectra of pyridine and pyridine‐d 5 were measured. The vibrational analysis of the nπ* absorptionspectrum and the preresonance Raman effect showed that the CH out‐of‐plane bending vibration ν10a (a 2) (of the ground and excited‐state frequencies 886 and 331 cm−1 for pyridine) is responsible for the vibronic coupling between the lowest nπ* state and the second lowest ππ* state.