Ab Initio Molecular Dynamics with controlled pressure

Solid-State Polymerization of Acetylene under Pressure: Ab Initio Simulation

Physical Review Letters, 78(10):2008.
M. Bernasconi, G. L Chiarotti, P. Focher, M. Parrinello, and E. Tosatti (1997)


We have simulated by ab initio constant pressure molecular dynamics the solid-state polymerization of acetylene recently observed experimentally in the pressure range 3.5–14 GPa. We have found a massive polymerization only at much higher pressure (25 GPa). However, we have also found that a triplet exciton self-trapped on a single, cis-bent molecule in crystalline acetylene is a very effective polymerization seed at lower pressure ( 9 GPa), much closer to the experimental threshold. Therefore, we propose that the polymerization observed experimentally is possibly catalyzed by a similar seed. We predict that injection of triplet excitons would greatly enhance the polymerization rate.

URL: http://dx.doi.org/10.1103/PhysRevLett.78.2008