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

The optical absorption properties of gold nanoparticles 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, 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.