Infrared frequency-modulation measurements of absolute rate coefficients for Cl+HD -> HCl(DCl)+D(H) between 295 and 700 K

Absolute rate coefficients and HCl branching fractions for the Cl + HD reac tion have been measured. The rate coefficient for Cl + HD is fit well by k( 1) = (1.28 +/- 0.18) x 10(-16) T-1.67 e(-(1646) (+/- 60)/T) cm(3) molecule( -1) s(-1), approximately 30% smaller than the mean of literature rate coeff icients for Cl + H-2 and D-2. The branching fraction into the HCl channel i s 0.67 +/- 0.09 at 295 K and decreases at higher temperature. The present r esults agree well with literature measurements of relative rates, confirmin g different isotope effects in thermal conditions than in molecular beam me asurements. (C) 1999 Elsevier Science B.V. All rights reserved.