Time-Dependent Density Functional Theory Studies of Optical Properties of Au Nanoparticles: Octahedra, Truncated Octahedra, and Icosahedra

The optical absorption properties of gold nanopartides are investigated theoretically. A time-dependent density functional theory approach is employed to determine excitation energies for a set of three structural shapes: octahedra, truncated octahedra, and icosahedra (Au-n,functional. The n = 6-85) in several charge states that correspond to electronic shell closings. Octahedral Au-n clusters with n = 6-85, truncated octahedral Au-n clusters with n = 13-79, and icosahedral Au-n clusters with n = 13-55 are examined. The optimization calculations use the BP86/DZ.4f level of theory, and the excitation energy calculations employ the LB94 functional. The Amsterdam Density Functional code was used for all calculations.