AB-INITIO MOLECULAR-DYNAMICS STUDY OF METALLOCENE-CATALYZED ETHYLENE POLYMERIZATION - TEMPERATURE EFFECTS

The feasibility of using ab initio molecular dynamics simulations to s tudy chemical reactions is illustrated by further studies on ethylene insertion into a bridged bis (cyclopentadienyl) methylzirconocene. Pre vious observation that the insertion is extremely fast, suggesting the absence of an energetic barrier, is further supported by results obta ined from simulations at various temperatures. In view of the short ti me span (170 fs) for insertion, coupling to an external heat bath cann ot be justified. Therefore, a microcanonical molecular dynamics simula tion starting at T = 0 K was performed. This simulation also revealed extremely fast ethylene insertion, which was accompanied by a temperat ure rise of a few hundred kelvin.