ANHARMONICITY EFFECTS IN CLUSTER ISOMERIZATION

The dynamics of Na4Cl4 clusters is explored and various methods of calculating cluster reaction rates are compared. The Na4Cl4 cluster undergoes isomerization from a low temperature cube to ladder and ring forms. The potential surface is dotted with low barriers such that back and forth reactions take place and at equilibrium significant concentrations of the ladder and the ring forms are present. Molecular dynamics and statistical methods of calculating rate coefficients are compared and the effects of internal energies and anharmonicities on the rate coefficients are discussed. The effects of a non-steady state between an activated molecule and a transition state on the energy-dependent RRKM rate coefficient are evaluated.