Charge separation and polymerization of hydrocarbons at an ultrahigh pressure

Ab initio molecular dynamics simulations have been performed as a function of density for a disordered sample of butadiene (CH2=CH-CH=CH2) at ambient temperature. At high density the system spontaneously reacts, in the ground state, with an ionic mechanism to mainly produce trans poly-butadiene chains. The reaction mechanism has been characterized. The pressure strongly modifies the molecular dipole generating cooperative phenomena in the sample.