THE INFLUENCE OF THE ATTRACTIVE WELL ON NEAR AND NONRESONANT VIBRATIONAL-ENERGY TRANSFER IN THE GAS-PHASE - CO(V=1) DEACTIVATED BY METHANE DEUTEROISOMERS

Rate constants for the vibrational deactivation of (CO)-C-12-O-16(upsi lon = 1) and of (CO)-C-13-O-18(upsilon = 1) by CH4 have been measured down to 70 K. For these non-resonant processes there is a flattening o f the temperature dependence of the rate constants at the lowest tempe ratures. The temperature dependence of the rate constants for the near -resonant deactivation of (CO)-C-12-O-16(upsilon = 1) by CD3H and CD4 is qualitatively different; below 80 K the rate constants fall off rap idly with temperature. It is considered that this is due to the trappi ng of the collision partners in the attractive well, while no trapping can occur for the highly exothermic energy transfer processes. (C) 19 97 Elsevier Science B.V.