DIRECT MEASUREMENTS OF REMOVAL RATES OF CHF((X)OVER-TILDE(1)A'(0,1,0)) AND CFCL((X)OVER-TILDE(1)A'(0,1,0)) BY NITROGEN-OXIDES (NO, NO2 AND N2O)

Direct measurements of the rate constants for collisional removal of v ibrationally excited electronic ground states CHF((X) over tilde(1)A'( 0,1,0)) and CFCl((X) over tilde 1A'(0,1,0)) species by Ar, NO, N2O and NO2 are reported. Both CHF((X) over tilde(1)A'(0,1,0)) and CFCl ((X) over tilde(1)A' (0,1,0)) fragments were prepared by infrared multiphot on dissociation, IRMPD, from the precursors CH2F2 and CHFCl2, respecti vely. Absolute second-order rate constants (k(Q)) for the removal of C HF( (X) over tilde(1)A'(0,1,0)) by NO, N2O and NO2 were measured and f ound to be as follows: (k(Q)/10-(12) cm(3).molecule(-1).s(-1)): 26.7 /- 0.27, 2.55 +/- 0.15 and 11.6 +/- 0.6 independent of fluence. These are much faster than the corresponding rate constants for the vibratio nal ground states (Table 1). CFCl((X) over tilde(1)A'(0,1,0)) is also removed by nitrogen oxides at higher rates than that of its ground sta te, and the values for Ar, NO, N2O and NO2 are (1.73 +/- 0.22) x 10(-2 ), 0.453 +/- 0.03, 1.05 +/- 0.10 and 0.257 +/- 0.01 (in 10(-12) cm(3). molecule-(1).s(-1) units), respectively. The contribution of the vibra tional energy in one of the reactants to the overall removal rates of the reaction, and the competitive V-V energy transfer are discussed.