Sum-rule approach in the theory of charged self-compressed dielectric droplets

The formal density-functional theory for neutral droplets that experience a spontaneous deformation is developed. The perturbative analytical expressi ons for the size corrections to the chemical potential, surface tension, an d atomic density are derived from the condition of mechanical equilibrium, using a power series expansion in the inverse of droplet radius R. In this way, the determination of these corrections is reduced to a calculation of the quantities for a liquid with a flat surface. It is shown that the size compression and tension of density occur in the 1/R and 1/R-2 orders, respe ctively. The sizes of charged, rigid and elastic, the so-called critical cl usters, for which the binding energy is close to zero, are calculated for A r-N(-) Kr-N,Kr- Xe-N(-) and Ar-N(+), Ne-N(+), He-N(+). The results show sig nificant contribution of self-compression to the binding energy of excess e lectron and a negligible influence on the positron binding. (C) 2001 Elsevi er Science B.V. All rights reserved.