A theoretical study of the dynamics of the Al + H2O reaction in the gas-phase

The dynamics of the Al + H2O reaction in the gas phase has been studied by means of TST and RRKM theories, including the treatment of tunneling. The main reaction path involves isomerization into a HAlOH species, which dissociates into AlOH + H. There is a second mechanism which involves hydrogen atom elimination from a Al-OH2 complex, but it only becomes relevant at very high temperatures. Our theoretical results for the variation of the rate coefficient with temperature are coherent with the experimental findings [R. E. McClean, H. H. Nelson, M. L. Campbell, J. Phys. Chem. 97 (1993) 9673] in the sense that they can be fitted to a double exponential form. Our explanation for that behavior is the variation of the transmission coefficient with temperature. We find formation of AlO + H-2 to be insignificant and the lifetime of Al-OH2 much larger than that of HAlOH. (C) 2011 Elsevier B. V. All rights reserved.