Abstract
The thermodynamic and structural properties of methanol clusters (CH3OH) N , N=5–15, 20, 30, 60, 128, 256 and the bulk liquid have been investigated using Monte Carlo simulation. Calculated properties as a function of size include electrostatic and dispersive contributions to the configurational energy, configurational heat capacities,fractal dimension, density profiles, order parameters characterizing dipole and bond vector orientation, and the Lindemann index. The clusterheat capacities as a function of N possess an interior maximum near N=128 and converge to the bulk value from above. Monocyclic, semiplanar structures are found to persist at liquidlike temperatures up to about N=12, followed by bi‐ and polycyclic structures for N=13–20, with the larger clusters gradually becoming more spherical. The average density of the larger clusters is fairly well represented by the bulk value. For clusters with 30 or more molecules, there is a net tendency for the molecular dipoles to lie flat on the cluster surface. The observed trends in heat capacities, density profiles, and dipole alignments parallel to the cluster surface are likely to be general features of clusters of polar molecules.