Ultraviolet Absorption of Pyrazine Vapor Due to n — π Transition

Abstract

The near ultraviolet absorption spectrum of pyrazine vapor was photographed and measured. A tentative vibrational analysis was made for some of the bands in the longest wavelength discrete band system (3200 A system), due to the n — π transition. The spectral band feature shows that the 3200 A system is a superposition of two absorption systems which belong to different electronic transitions. It appears that this conclusion is also supported by simple theoretical considerations.