Pii: S0032-3861(00)00519-x
نویسندگان
چکیده
Short-chain branching in polyethylene, which involves a six-centre transition state, is studied by ab initio quantum mechanics up to the QCISD(T) level. The calculation gives a (low-pressure) activation energy of 73 kJ mol and a frequency factor of 4:8 × 10 s: The frequency factor for this six-centre transition state is expected to be of acceptable accuracy and also applicable to homologous systems, such as short-chain branching to polymer in acrylates. These results overestimate the amount of ethylene short-chain branching observed in experiment, but the discrepancy is within the uncertainties of both experiment and calculation. q 2000 Elsevier Science Ltd. All rights reserved.
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