The spontaneous polarization during the cryocondensation of polar molecules

The creation of an electrically polarized layer during the condensation process of polar gases onto a deeply cooled substrate is briefly described. This electret phenomenon can appear in any temperature range where solidification of a gaseous phase on a cold substrate is possible. The magnitude and the sign of the surface charges depend on the condensation temperature only. Also, the stability of the surface charges of the condensate depends strongly on temperature. No such an effect of polarization is observed for condensates of non-polar molecules. The main source of the observed electret effect seems to be an orientation of the molecular dipoles. The results available up to now, do not yet allow a satisfactory explanation of the observed spontaneous polarization effect.