Direct molecular dynamics propagation mechanisms

Eckart conditions, Renner-Teller effect, triatomic molecules, 610-615 Ehrenfest dynamics, direct molecular dynamics error sources, 403—404 Gaussian wavepacket propagation, 378-383 molecular mechanics valence bond (MMVB), 409-411... 

The existence of a dynamic equilibrium between dormant (covalent) and active (ionic) species in controlled carbocationic polymerizations had been debated for years. It has been argued that under certain conditions, polarized covalent species can directly react with monomer examples are the pseudocationic mechanism proposed for the polymerization of styrene initiated by perchloric acid (123,124) (Fig. 5) or the two-component group transfer polymerization proposed for the polymerization of isobutylene initiated by the dicumylacetate/BCls system (125) (Fig. 6). Recent results and theoretical considerations support the now generally accepted view that the true active species are ions, and the dormant species serve as a reservoir from which the propagating ion pairs are formed (126-131). The existence of a dynamic equilibrium between dormant and active species and the ability to suppress the formation of free ions made possible the synthesis of pol5miers with controlled molecular architecture via carbocationic polymerization. 

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