Molecular dynamics study of dimer formation in three dimensions

Molecular dynamics is used to study a classical model of dimer formation by three-body collisions in three dimensions. The mole fractions for both stable and metastable dimers are obtained for T*=0.85, 1.1, and 2.2 and compare well with the equilibrium statistical mechanics results. The dimer internal energy and vibrational and rotational energy distributions are obtained and appear to be qualitatively consistent with equilibrium internal distributions. The temperature dependence of K, the reaction rate, varies approximately as T*−=5/8. From this it is concluded that the steric factor P for the formation of stable dimers lies in the range 0.05–0.1 and is even smaller than the previous two-dimensional results.