Abstract
The effects of temperature and conformerisation on the evaporation/condensation coefficient (beta) and the evaporation rate (gama) for ndodecane nano and microdroplets are analysed using quantum chemical DFT calculations for several ensembles of conformers of ndodecane molecules in the gas and liquid phases. To highlight the underlying physics of the evaporation/condensation process, the internal molecular dynamics (IMD) effects of ndodecane molecules on heat transfers between gas and liquid phases are investigated. Bond energies, the Gibbs free energies of internal dynamics of a set of ndodecane conformers, and the energies of the molecules colliding with the surface of an ndodecane nanodroplet are studied using the quantum chemical approach. The values of "gama" and "beta" are shown to be sensitive to the changes in the Gibbs free energy (G) of conformers in the gas and liquid phases. The values of G referring to internal dynamics in ndodecane conformers are estimated using the quantum continuum solvent model, ωB97XD/ccpVTZ chemistry electronic model and programs Gaussian 09, CP2K and MSTor in which conformational, torsional and vibrational effects are taken into account. Conformerisation effects leading to a decrease in "gama" cause an increase in the evaporation rate and decrease in the evaporation time compared with those computed without consideration of these effects. The latter are attributed to anharmonicity effects inferred from the coupling of vibrational, rotational, torsional and conformational dynamics. This coupling leads to favourable changes in the Gibbs free energy of evaporation of certain conformers during their transfer from the liquid into the gas phase. Without consideration of these effects, the evaporation rate can be underestimated by up to an order of magnitude.
Original language  English 

Pages  13 
Number of pages  3 
Publication status  Published  24 Mar 2015 
Event  Asian Nano Forum Conference, ANFC 2015  Kish Island, Iran, 811 March 2015 Duration: 24 Mar 2015 → … 
Conference
Conference  Asian Nano Forum Conference, ANFC 2015 

Period  24/03/15 → … 
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Profiles

Sergei Sazhin
 School of Computing, Engineering & Maths  Professor of Thermal Physics
 Advanced Engineering Centre
Person: Academic