The Determination of Microscopic Surface Tension of Liquids with a   Curved Interphase Boundary by Means of Positron Spectroscopy
  The method for determination the microscopic surface tension $\sigma(R)$ of nanobubbles is developed based on the new elaboration of the positronium bubble model. In contrast to existing structureless Ps bubble models, our version contains experimentally known molecular characteristics of liquids. The relationship, similar to Tolman's equation, between $\sigma(R)$ and the radius $R$ of the Ps bubble is derived on a microscopic basis. Numerical values for $\sigma(R)$ are determined for a large number of liquids and liquified gases. The results are in agreement with the theoretical expectations and independent evaluations, available in literature. 
Sergey V. Stepanov, Vsevolod M. Byakov, Olga P. Stepanova