First principles study of three-dimensional polymers of C-60: Structure, electronic properties, and Raman spectra

We report ab initio calculations on the structure, electronic properties, and Raman spectra of six crystalline phases of three-dimensional (3D) polymeric C-60, all belonging to the Immm space group inferred experimentally from single crystal x-ray diffraction data [S. Yamanaka et al., Phys. Rev. Lett. 96, 76602 (2006)]. All the structures display interplanar bonding connecting a C-60 cage with its eight nearest neighbors and differ in the type of in-plane intercage bonds. Raman spectra reveal high frequency peaks (1700-1800 cm(-1)) due to stretching modes of ethyleniclike bonds which might correspond to Raman peaks at similar frequencies, detected experimentally on pressurized C-60 polymers [K. P. Meletov et al., Chem. Phys. Lett. 341, 453 (2001)].