Original Publication Date
The Journal of Chemical Physics
DOI of Original Publication
Date of Submission
The critical supersaturations (S c ) required for the homogeneous nucleation of acetonitrile, benzonitrile, nitromethane, and nitrobenzene vapors have been measured over wide temperature ranges using a thermal diffusion cloud chamber. At T r =0.44, the experimental results are higher than the predictions of the classical nucleation theory by 20% (CH3NO2), 50% (CH3CN), 57% (C6H5NO2), and 112% (C6H5CN). This trend correlates well with the dipole moments and to a lesser extent with the polarizabilities of these substances. Corresponding states of simple fluids and scaled nucleation law show that CH3CN and CH3NO2 have similar nucleation behavior which is different from that of C6H5CN and C6H5NO2. Correlations with other less polar substances are examined. The scaled law, with Ω (the excess surfaceentropy per molecule) determined from the temperature dependence of the bulk surface tension, gives a better description of the experimental results than the classical theory with the exception of nitromethane. The results suggest that the classical theory does not take proper account of the dipole–dipole interaction in calculating the free energy of the embryonic droplets.
Wright, D., Caldwell, R., & Moxely, C., et al. Homogeneous nucleation in supersaturated vapors of polar molecules: Acetonitrile, benzonitrile, nitromethane, and nitrobenzene. The Journal of Chemical Physics, 98, 3356 (1993). Copyright © 1993 American Institute of Physics.
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VCU Chemistry Publications