Entropy features of the PeTa effect during phase transformations of water

The article discusses a hypothesis put forward by V. A. Tatarchenko and M. E. Perelman. According to it, the first order phase transition during vapour condensation or melt crystallisation (PeTa effect) is accompanied by the appearance of nonthermal radiation of the media. The generally accepted point of view is that the latent heat of phase transformation can only be released in the form of heat. When the authors of the hypothesis tried to prove the existence of the effect of nonthermal radiation and considered the facts confirming it, they did not take into account the peculiarities of the initial and final states of the medium (i.e. their entropy). To clarify the physics of the process of liquid crystallisation and to consider the possibility of nonthermal radiation, we studied the peculiarities of water crystallisation and the formation of ice. This isthe process the authors referred to in order to prove their hypothesis. It was shown that in various experiments, it is necessary to consider both the state (structure) of the initial water samples and the formed ice, which can consist of various crystalline modifications with chaotic packing. These features of initial and final states, i.e. the entropy of water and ice samples in real experiments and under observed natural phenomena, make it more difficult to assess the characteristics of a possible radiation. The entropy of the initial and final states was determined by the procedure of the system preparation and the peculiarities of the phase transition dynamics. Its values depend on macroscopic parameters, as well a s on themicrostructure of the media, the determination of which is a very challenging task in each specific case. In addition, in many cases, we have to deal with metastable media, for which it is necessary to take into account the influence of fluctuations on the process of the phase transition. Therefore, the concepts of equilibrium thermodynamics are not applicable to them. However, these are the media where non-heat radiations may occur in accordance with the laws of self-organisation in nonlinear weakly nonequilibrium objects. This work shows a method for preparing low-entropy medium with its subsequent phase transformation into ice. To do so we conducted an experiment which involved freezing concentrated alcohol in order to obtain deeply supercooled water. It appears that to find the characteristics of the PeTa radiation it is necessary to takeinto account the entropy constraints for each specific case, which will allow assessing the spectrum of possible non-heated radiations and their characteristics.