DECOMPOSITION AND POLYMERIZATION OF SOLID CARBON-MONOXIDE UNDER PRESSURE

By performing constant-pressure deformable-cell ab initio molecular dy namics simulations we have studied the pressure-induced chemical insta bility of CO above 5 GPa. The simulation shows that, contrary to previ ous speculations, polymerization proceeds without CO bond dissociation . The resulting polymer consists of a disordered network of small poly carbonyl (CO)(n) chains connecting fivefold C4O cycles. The computed v ibrational spectra and electronic gap agree very well with (and shed l ight on) very recent experimental data.