Experimental detection of nucleation rate surface singularity

As a rule, the modern theories of nucleation represent only modifications o f classical theory, and they still remain unsuitable for quantitative predi ction of experimental results. In order to create the universal description of supersaturated vapor nucleation, as well as evaluate other theories, we need to get the reliable experimental results. Now experimental skills are high enough for precision measurements of the vapor nucleation rates as we ll as for detecting and evaluating, for example, temperatures of phase tran sitions in the new phase critical embryos. That is, one can find experiment ally the singularity of the nucleation rate surface at conditions for the c ritical embryo phase transitions. Visual analysis of the experimental resul ts has the low potential to detect the nucleation rate surface singularity and the surface singularity can be missed sometimes. One major problem for singularity detection is the noise of experimental results. This problem st ill exists even if one has experimental results of high accuracy. The condi tion for surface continuity and monotony could be applied as a criterion fo r analysis of experimental data for the vapor nucleation rates. The criteri on is tested for the broad spectrum of the experimental results in the vapo r nucleation. As an example of the criterion being used, the experimental r esults for the n-pentanol-water binary system of nucleation have been analy zed. A peculiarity of this system is the existence of a miscibility gap bet ween the components. It was found that the criterion as a function of n-pen tanol mole fraction has the singularity in the vicinity of this gap. This s ingularity was smoothed in the experimental results presentation and omitte d in the original research. The proposed criterion can be used to search th e experimental data set singularity as a function of their variable(s). (C) 2000 American Institute of Physics. [S0021-9606(00)50904-0].