COMPUTATIONAL STUDIES OF ATMOSPHERIC CHEMISTRY SPECIES .12. COMPUTED GAS-PHASE THERMODYNAMICS OF THE N2-O2 COMPLEXES

The thermodynamics of the gas-phase dimerizations of N2 and O2 has bee n evaluated in terms of partition functions, constructed using quantum chemical ab initio computations. Two different evaluations of the dim erization energetics have been employed and two minimum-energy structu res of the dimer (a linear structure and a T shape) have been consider ed. In both sets, the structures co-exist, although at temperatures re levant for atmospheric conditions the T-shaped species is more populat ed. The isomeric interplay is reflected in an enhancement of heat capa city, especially at very low temperatures. For the dimerization equili brium constant, an interval in which the true value should bc applicab le is suggested.