The Σu−3←X 3Σg− electronic spectrum of linear C4 in the gas phase

Abstract

The Σ3Σu−←X 3Σg− electronic absorption spectrum of linear C4 has been detected in the gas phase. The origin and several vibronic transitions have been recorded by means of cavity ring down spectroscopy through a supersonic planar plasma. The origin band is found at 26 384.9(2) cm−1 (∼379 nm). A partly rotationally resolved origin band spectrum yields a value of B0′=0.1570(5) cm−1 for the electronically excited Σ3Σu− state.