COMPUTATIONAL STUDIES OF ATMOSPHERIC CHEMISTRY SPECIES .9. COMPUTED GAS-PHASE THERMODYNAMICS OF N2 ASSOCIATION

The thermodynamics of the gas-phase N2 dimerization has been computed in terms of partition functions constructed on the basis of ab initio quantum-chemical computations. Two different evaluations of the dimeri zation energetics have been employed, indicating four and three (N2)2 minimum energy structures. In both sets. two particular structures co- exist at temperatures relevant for atmospheric conditions. Enhancement of heat capacity through this isomerism is felt at very low temperatu res only. For the dimerization equilibrium constant, an interval in wh ich the true value should be present is suggested.