Absolute rate constants for the removal of CH2 (ã 1A1) by Ar, NO and H2 have been measured over the temperature range 295-431 K using laser flash kinetic absorption spectroscopy. For NO and H2, no marked temperature dependence is observed. For Ar, the rate constants increase by some 50% over this range and the results are discussed in terms of a theoretical model which relates the removal rate constants to the fractional population of CH2 (ã 1A1) in states perturbed by nearby triplet levels. © 1991.
