@article {4897, title = {Measurements of Mu+NO termolecular kinetics up to 520 bar: isotope effects and the Troe theory}, journal = {Physical Chemistry Chemical Physics}, volume = {2}, number = {4}, year = {2000}, note = {ISI Document Delivery No.: 281JDTimes Cited: 3Cited Reference Count: 58}, pages = {621-629}, type = {Article}, abstract = {The recombination reaction Mu + NO + MMuNO + M (M = He, N-2, CH4) has been studied by the muon spin relaxation/rotation (mu SR) technique up to 520 bar at room temperature. The reaction remains in the low pressure regime throughout. The measured termolecular addition rate constant in N-2, 8.8 +/- 0.3 x 10(-33) cm(6) s(-1), is essentially the same as that found in our earlier study at pressures below 60 bar [J. J. Pan et al., J. Phys. Chem., 1995, 99, 17160]. It is somewhat smaller in He, 7.7 +/- 1.0 x 10(-33), but larger in CH4, 12.8 +/- 2.0 x 10(-33). The Mu + NO reaction is about five times slower than the corresponding H + NO reaction. The strong collision limits of the rate constants for three H-isotopes (Mu, H, D) reacting with NO have been estimated with Troe{\textquoteright}s formalism for unimolecular dissociation in the low pressure regime, based on the ab initio potential energy surface of Guadagnini et al. [J. Chem. Phys., 1995, 102, 774]. The Troe calculations give less than satisfactory agreement with experiment with the corresponding weak collision factor, beta(c), higher than expected by a factor of similar to 2 for H + NO. The calculated kinetic isotope effect in the strong collision limit for Mu/H is weaker than the measured effect by a factor of two giving an apparent large isotope effect in this factor, beta(c)(Mu) approximate to 1/2,beta(o)(H), possibly due to mode specific collisional stabilization.}, keywords = {COLLISIONAL ENERGY-TRANSFER, DISSOCIATION, ELECTRON-SPIN EXCHANGE, GAS-PHASE, HIGH-PRESSURES, HNO, muonium, RATE CONSTANTS, relaxation, THERMAL UNIMOLECULAR REACTIONS}, isbn = {1463-9076}, url = {://000085154400025}, author = {Pan, J. J. and Arseneau, D. J. and Senba, M. and Fleming, Donald G. and Himmer, U. and Suzuki, Y.} }