A transformation of carbon dioxide to nonmolecular solid at room temperature and high pressure

Raman and infrared absorption spectra of solid carbon dioxide (CO2) have been measured at high pressures up to 80GPa and room temperature. The broadening and weakening of lattice vibrational signals and the disappearance of molecular vibration were detected at 65GPa by means of the Raman and infrared absorption experiments, respectively. The present Raman spectral feature is exactly the same as that of amorphous CO2 synthesized around 600K and 60GPa [M. Santoro et al., Nature (London) 441, 857 (2006)]. It is demonstrated that the polymerization of CO2 proceeds even at room temperature and almost independently of temperature.