Gun'ko, Vladimir M.; Nasiri, Rasoul; Sazhin, Sergei S.
Effects of the surroundings and conformerisation of n-dodecane molecules on evaporation/condensation processes
JOURNAL OF CHEMICAL PHYSICS, 142 Art. No. 034502, JAN 21 2015

The evaporation/condensation coefficient (beta) and the evaporation rate (gamma) for n-dodecane vs. temperature, gas pressure, gas and liquid density, and solvation effects at a droplet surface are analysed using quantum chemical density functional theory calculations of several ensembles of conformers of n-dodecane molecules in the gas phase (hybrid functional SMD/omega B97X-D with the cc-pVTZ and cc-pVDZ basis sets) and in liquid phase (solvation method: SMD/omega B97X-D). It is shown that beta depends more strongly on a number of neighbouring molecules interacting with an evaporating molecule at a droplet surface (this number is estimated through changes in the surface Gibbs free energy of solvation) than on pressure in the gas phase or conformerisation and cross-conformerisation of molecules in both phases. Thus, temperature and the surrounding effects at droplet surfaces are the dominant factors affecting the values of beta for n-dodecane molecules. These values are shown to be similar (at reduced temperatures T/T-c < 0.8) or slightly larger (at T/T-c > 0.8) than the values of beta calculated by the molecular dynamics force fields (MD FF) methods. This endorses the reliability of the previously developed classical approach to estimation of beta by the MD FF methods, except at temperatures close to the critical temperature. (c) 2015 AIP Publishing LLC.


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