A theoretical study of vibrational properties of neutral and cationic B12 clusters

Calculations based on density functional theory predict the ground state of B-12 and B-12(+) to be a convex planar configuration with C, symmetry. A small ionization-induced structural change in B,, is also predicted. It is suggested that multicentered bonds together with delocalized charge density are dominant factors in stabilizing the planar configuration over 3D configuration for B-12 and B-12(+). The calculated vibrational frequencies lie in the range of 200-1328 cm(-1) in which the high-frequency modes are associated with asymmetric stretching of the boron atoms located at the cluster surface. The infrared spectra of both neutral and cationic B-12 show similar infrared active modes in the high-frequency region, but different modes in the low-frequency region due to dissimilar atomic charges in the cationic B-12. The combined effect of charge delocalization and reduced dimensionality is reflected in the calculated static dipole polarizability of these clusters. (c) 2005 Wiley Periodicals, Inc.