Computer Simulation of Molecular Interactions in Supercritical Solvents
Abstract
Integral equation calculations were performed on two model supercritical mixtures: naphthalene in carbon dioxide (non-volatile solute; attractive mixture) and neon in xenon (volatile solute; repulsive mixture). Both systems were studied at high dilution, at supercritical temperature, and over a broad range of densities. The attractive system exhibited significant short- ranged solvent enrichment around the solute. The difference between the solvent density averaged over three solvation shells, and the bulk solvent density was found to be more pronounced between 50 and 80% of the solvent's critical density. In contrast, the repulsive system exhibited local solvent depletion near the solvent's critical point. The extent of the solvation region responsible for determining the solute's chemical potential varies between three and five solvent diameters for the attractive mixture, with the maximum occurring near the solvent's critical density. At 60% of the solvent's critical density, the local concentration of naphthalene molecules around each other is almost ten times higher than in the bulk. Dynamic simulations of pyrene in carbon dioxide revealed insignificant solute-solute aggregation. The mean lifetime of transient solute dimers, roughly 0.8 picoseconds, was found not to chance even when the bulk density was varied by a factor of four. Molecular dynamics simulation, Integral equation calculations, Molecular interactions in- supercritical solvents.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 30, 1993
- Accession Number
- ADA274977
Entities
People
- P. G. Debenedetti
Organizations
- Princeton University