Raman cross section for the pentagonal-pinch mode in buckminsterfullerene C60

The Raman cross section for the pentagonal pinch mode of C60 at 1469 cm−1 has been determined at a laser excitation wavelength λL = 752.5 nm. The experimental value, dσ/dΩ = (2.09 ± 0.29) × 10−29 cm2/sr, is found to be in good agreement with predictions from an ab initio calculation based on density functional perturbation theory. A simple bond polarizability model with parameters obtained from hydrocarbon Raman measurements yields Raman intensities in C60 within one order of magnitude of the experimental data.