Infrared diode laser kinetic spectroscopy of the ν3 band of C3

Abstract
Infrared diode laser kinetic spectroscopy was applied to reaction intermediates generated by the photolysis of diacetylene and allene at 193 nm. A strong band was observed around 2040 cm1 and was assigned to the ν3 band of C3 . The observed spectrum was analyzed by using an energy level expression for a linear molecule; higher‐order centrifugal distortion terms were necessary to be included in the least‐squares fit. The band origin was determined to be 2040.0198 (8) cm1. The rotational and centrifugal distortion constants obtained suggest the presence of a potential barrier at the linear configuration in both the ground and ν3 states.