COMPUTATIONAL STUDIES OF ATMOSPHERIC CHEMISTRY SPECIES .14. GAS-PHASEASSOCIATION OF O-2 - A COMPUTATIONAL THERMODYNAMIC STUDY

The thermodynamics of the gas-phase 02 dimerization have been computed in terms of partition functions, supplied with parameters from quantu m-chemical ab initio computations. Two different evaluations of the di merization energetics have been employed and three different isomers o f the dimer considered. In both sets the non-linear structures co-exis t at temperatures relevant for atmospheric conditions. Enhancement of heat capacity through this isomeric interplay is quite large at very l ow temperatures. For the total dimerization equilibrium constant an in terval, in which the true value should be present, is suggested.