Simultaneous determination of mass and thermal accommodation coeincients from temporal evolution of an evaporating water microdroplet

Scattering of coherent light by an evaporating droplet of pure water several micrometres in size was investigated. The droplet was levitated in an electrodynamic trap placed in a small climatic chamber. The evolution of the droplet radius and the evolution dynamics were investigated by means of analysing the scattering patterns with the aid of Mie theory. A numerical model of droplet evolution, incorporating the kinetic effects near the droplet surface, was constructed. Application of this model to the experimental data allowed us to determine the mass and thermal accommodation coefficients to be alpha(C) = 0.12 +/- 0.02 and alpha(T) = 0.65 +/- 0.09, respectively. This model enabled us to determine with high precision the temperature evolution of the droplet and the relative humidity in the droplet vicinity.