INVESTIGATIONS OF THE REACTIONS OF (CH2)-C-1 ((A)OVER-TILDE(1)A(1) (V=0,1)) WITH H2O, D2O AND HCL

The reactions of (CH2)-C-1(<(a)over tilde(1)> A(1)) in its vibrational ground state ((CH2)-C-1(v = 0)) and with single excited bending mode ((CH2)-C-1(v = 1)) with the reactants H2O (1), D2O (2) and HCl (3) wer e investigated with a LIF apparatus under quasistationary and first or der conditions. (CH2)-C-1 was produced via ketene photolysis at 308 nm ((CH2)-C-1(v = 0) and (CH2)-C-1(v = 1)) and at 336 nm (only (CH2)-C-1 (v = 0)). The evaluation of the kinetic data of (CH2)-C-1(v = 0) gave different results for both wavelength. At lambda = 336 nm obtained rat e constants were in general higher compared to those at lambda = 308 n m. The measurements at lambda = 308 nm therefore seem to be influenced by secondary processes and they do not give the 'real rate constant'. (CH2)-C-1(v = 1) reacts faster with all three investigated reactants than (CH2)-C-1(v = 0) does. Vibrational deactivation with unusual high rate constants may explain these different reactivities of (CH2)-C-1( v = 0) and (CH2)-C-1(v = 1), but can only in part explain differences for the two (CH2)-C-1(v = 0) measurements. The following rate constant s were measured at T = 295 K (in cm(3) . mol(-1). s(-1)): k(1)((CH2)-C -1(v = 0)) = (1.45 +/- 0,1). 10(14), k(1)((CH2)-C-1(v = 1)) = (2.3 +/- 0.2). 10(14), k(2)((CH2)-C-1(v = 0)) approximate to 1.1 . 10(14), k(2 )((CH2)-C-1(v = 1)) = (1.75 +/- 0.15). 10(14), k(3)((CH2)-C-1(v = 0)) = (2.0 +/- 0.2). 10(14), and k(3)((CH2)-C-1(v = 1)) = (2.2 +/- 0.2). 1 0(14). In the range from 255 K to 475 K the rate constants of the reac tions of (CH2)-C-1(v = 0,1) with H2O and D2O show a significant depend ence on temperature T which can be expressed by T--n with n = 0.6 to 0 .8. The channel of the reaction of (CH2)-C-1 + H2O leading to CH3 + OH was found to contribute 50 +/- 15% to the total reaction, thus being the main channel at p less than or equal to 14 mbar. Formaldehyde coul d not be detected as a product of (1).