Molecular simulated conversion data, parameter

Table 13.3 presents the expressions for the rate constants applied in this work. The parameters are taken mostly from the work of Xie et al. [6], A distinctive feature of the numerical simulation of the influence of gel effect on the termination in the polymer-phase is described by a relation proposed by Kipparisides et al. [5], This combination of parameters gives realistic results on modeling both the reaction dynamics and the development of the molecular-weight distribution, reproducing closely experimental data (see Figure 13.6). The subscript 1 refers to the monomer phase, 2 to the polymer phase, and 22 to the polymer-phase after the critical conversion Xf. In addition, Table 13.4 presents first-order constants for usual initiators. 

The recently proposed semi empirical method for simulation of photochemical processes and calculation of quantum yields of reactions has been modified. The specific form of double minimum potential energy surfaces of the molecules involved in the conversion has been considered in a more correct manner. It has been shown that the number of molecular models parameters can be reduced by two-thirds compared with the approach used previously. The quantum yields of photochemical transformations of six dienes into their cyclic isomers have been calculated. Substantially better quantitative agreement of the calculated values with the experimental data has been achieved for all the reactions. It has been shown that the model parameters have good transferability in a series of related molecules. 

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