Static polarizabilities of Na-n (n <= 9) clusters: An all-electron densityfunctional study

This paper presents static polarizabilities and polarizability anisotropies of sodium clusters up to nine atoms calculated in the framework of density functional theory. The calculations of the static polarizabilities and pol arizability anisotropies have been performed using a finite field approach implemented in the density functional program ALLCHEM. The calculations wer e of the all-electron type. Local and gradient-corrected exchange-correlati on functionals have been used. All molecular geometries were fully optimize d at both levels of theory. A vibrational analysis was performed in order t o discriminate between minima and transition state structures on the potent ial energy surfaces. Equilibrium geometries, bond distances, harmonic frequ encies, static polarizabilities, and polarizability anisotropies for sodium clusters up to the nonamer are presented. The obtained results are compare d with experimental data as well as with other theoretical results. The cal culated and experimental polarizabilities are in good agreement. For the tr imer and the hexamer, the effect of different isomers in the calculation of the polarizability was investigated. This work demonstrates that the used approach allows the prediction of reliable electro-optical properties of me tallic systems. (C) 1999 American Institute of Physics. [S0021-9606(99)3043 4-7].