Raman Spectrum of Diamond

TLDR

The prominent features in both the second‑order Raman spectra reported here and the second‑order infrared spectra are interpreted in terms of the critical points of the phonon dispersion curves established from neutron spectroscopy and on the basis of space‑group selection rules. The authors measured first‑ and second‑order Raman spectra of diamond with 4880 Å, 5145 Å Ar‑ion laser lines and 6328 Å He‑Ne laser at room, liquid‑nitrogen, and liquid‑helium temperatures, and performed polarization studies on both spectra. They observed a new weaker second‑order Raman band between 1600 and 2100 cm⁻¹ and identified the 1332 cm⁻¹ line as the zone‑center optical phonon with Γ^(25+) (F2g) symmetry.

Abstract

The first- and second-order Raman spectra of diamond were studied using the 4880 \AA{} and 5145 \AA{} lines of an Ar ion laser and the 6328 \AA{} line of a He-Ne laser. The spectra were recorded at room, liquid-nitrogen, and liquid-helium temperatures. In addition to the second-order spectrum previously reported by Krishnan, a new weaker second-order spectrum was observed in the range 1600-2100 ${\mathrm{cm}}^{\ensuremath{-}1}$. Polarization studies were carried out on both the first- and second-order spectra. From such studies it was established that the 1332-${\mathrm{cm}}^{\ensuremath{-}1}$ Raman line is the zone-center optical phonon with ${\ensuremath{\Gamma}}^{(25+)}$ (${F}_{2g}$) symmetry. The prominent features in both the second-order Raman spectra reported here and the second-order infrared spectra are interpreted in terms of the critical points of the phonon dispersion curves established from neutron spectroscopy and on the basis of space-group selection rules.