Near Ultraviolet Absorption Spectrum of Ethylpyrazine

Abstract Vibrational analysis of the electronic absorption spectrum of ethylpyrazine observed around 320 nm is carried out. The bands are ascribed to the longest wavelength one of the four possible π∗ ← n systems. A “vibronic” interaction between the excited state of this system and another excited state of the molecule is observed. A π∗ ← π system with practically no vibrational structure is also observed and discussed.