Theoretical investigation of the C-60 infrared spectrum

[摘要] A semiempirical model of the infrared (IR) spectrum of the C-60 molecule is proposed. The weak IR-active modes seen experimentally in a C-60 crystalline sample are argued to be combination modes caused by anharmonicity. The origin of these two-mode excitations can be either mechanical (anharmonic interatomic forces) or electrical (nonlinear dipole-moment expansion in normal mode coordinates). It is shown that the electrical anharmonicity model exhibits basic features of the experimental spectrum while nonlinear dynamics would lead to a qualitatively different overall picture.

[关键词] FORCE-CONSTANT MODEL;DOPED FULLERENES;VIBRATIONAL-MODES;SUPERCONDUCTIVITY;RAMAN;BUCKMINSTERFULLERENE;C60;SPECTROSCOPY;SCATTERING;FILMS