Collision width measurements of CO in combustion gases using a tunable diode laser

Abstract

A tunable diode laser was used to record fully resolved vibration-rotation absorption lines of CO in the combustion products of an atmospheric pressure methane-air flame. The measurements were made both at high temperature, in situ, and in gases cooled to room temperature. The in situ measurements were made on 26 lines in the 1 → 0, 2 → 1, and 3 → 2 vibrational bands of the CO fundamental. The room temperature measurements were performed on 19 lines in the 1 → 0 band. Results are presented for the dependence of the collision width, 2γ, on vibrational and rotational quantum numbers at 1850 and 300°K. The temperature exponent N, defined by the relation 2 γ 2 = 2 γ 1( T 2/ T 1) − N , was also determined and found to depend on rotational quantum number.