Ab initio molecular dynamics study of metallocene-catalysed ethylene polymerisation: Temperature effects

The feasibility of using ab initio molecular dynamics simulations to study chemical reactions is illustrated by further studies on ethylene insertion into a bridged bis (cyclopentadienyl) methylzirconocene. Previous observation that the insertion is extremely fast, suggesting the absence of an energetic barrier, is further supported by results obtained from simulations at various temperatures. In view of the short time span (170 fs) for insertion, coupling to an external heat bath cannot be justified. Therefore, a microcanonical molecular dynamics simulation starting at T = 0 K was performed. This simulation also revealed extremely fast ethylene insertion, which was accompanied by a temperature rise of a few hundred kelvin.