Vibrational relaxation in shock-heated mixtures of carbon monoxide with hydrogen halides

Abstract

Relaxation times have been measured for the overtone emission from shock heated CO to which small amounts of hydrogen halides were added. From the decrease in experimental relaxation time with concentration of hydrogen halide (HX) the rate constants for the reactions HX(V= 1)+ CO → HX(V= 0)+ CO were determined. The rate constants found, normalised to a pressure of one atmosphere, are given by the equations HCl, CO log₁₀(k/µs^–1 atm^–1)= 3.61 (± 0.41)– 47.6(±4)(T/K)^–1/3(T/K = 1200→ 2000 ) DCl, CO log₁₀(k/µs^–1 atm^–1)= 4.04(± 0.21)– 45.4(± 2.5)(T/K)^–1/3(T/K = 1350 → 1850) HBr, CO log₁₀(k/µs^–1 atm^–1)= 2.31(± 0.1)– 31.8(± 1)(T/K)^–1/3(T/K = 1200 → 2000) HI, CO log₁₀(k/µs^–1 atm^–1)= 2.47(± 0.2)– 29.0(± 2)(T/K)^–1/3(T/K = 1400 → 2000).