SELF-EXPANSION AND COMPRESSION OF CHARGED CLUSTERS OF STABILIZED JELLIUM

In a positively charged metallic cluster, surface tension tends to enh ance the ionic density with respect to its bulk value, while surface-c harge repulsion tends to reduce it. Using the stabilized jellium model , we examine the self-expansion and compression of positively charged clusters of simply metals. Quantal results from the Kohn-Sham equation s using the local density approximation are compared with continuous r esults from the liquid drop model. The positive background is constrai ned to a spherical shape. Numerical results for the equilibrium radius and the elastic stiffness are presented for singly and doubly positiv ely charged aluminum sodium, and cesium clusters of 1-20 atoms. Self-e xpansion occurs for small charged clusters of sodium and cesium, but n ot of aluminum. The effect of the expansion or compression on the ioni zation energies is analyzed. For Al-6, we also consider net charges gr eater than 2(+). The results of the stabilized jellium model for self- compression are compared with those of other models, including the SAP S (spherical averaged pseudopotential model). (C) 1996 John Wiley & So ns, Inc.