Affiliations: [a] Department of Physics, University of Texas El Paso, El Paso, TX, 79968, USA | [b] NSF CREST Center for Nanomaterials Characterization Science and Process Technology, Howard University, School of Engineering, Washington D.C. 20059, USA | [c] Department of Physics, University of Texas El Paso, El Paso, TX 79968, USA | [d] Center for Computational Materials Science, Code 6392, Naval Research Laboratory, Washington DC 20375, USA | [x] Department of Chemistry, University of Patras, Greece | [y] Departamento de Quimica, CINVESTAV, Centro De Investigacion Y De Estudios Avanzados, Av. Instituto Politecnico Nacional, 2508, A.P. 14-740, Mexico, D.F. 07000, Mexico
Abstract: We present a detailed investigation of static dipole polarizability of lithium clusters containing up to 22 atoms. We first build a database of lithium clusters by optimizing several candidate structures for the ground state geometry for each size. The full polarizability tensor is determined for about 5–6 isomers of each cluster size using the finite-field method. All calculations are performed using large Gaussian basis sets, and within the generalized gradient approximation to the density functional theory, as implemented in the NRLMOL suite of codes. The average polarizability per atom varies from 11 to 9 AAA, within the 8–22 size range and show smoother decrease with increase in cluster size than the experimental values. While the average polarizability exhibits a relatively weak dependence on cluster conformation, significant changes in the degree of anisotropy of the polarizability tensor are observed. Interestingly, in addition to the expected even odd (0 and 1 μB) magnetic states, our results show several cases where clusters with an odd number of Li atoms exhibit elevated spin states (e.g. 3 μB).
