A theoretical synthesis of polymers by using uniform localization molecular orbitals : proposal of an elongation method

The elongation method, a new approach to calculating the electronic structure of polymers efficiently, is proposed as a model for real polymerization reactions following the normal chain reaction processes of initiation, propagation, and termination. The calculations are carried out by repeating the uniform localization of wave functions with inclusion of the interaction between the end group of the cluster and an attacking molecule. As a first step of this treatment, the validity of our method is examined via application to regular and irregular model polymers consisting of hydrogen molecules at the extended Hückel level and comparing the results with those obtained from the conventional variational method. Furthermore, this treatment is performed on the real polymers such as polyethylene and polypropylene stereoisomers, and is proved to be reliable with advantages in computational time and storage. The approach is promising for application to very large systems on which direct variational calculations of the whole system are impossible. Moreover, it should be emphasized that this approach can mimic real reaction coordinates, or can be considered a theoretical synthesis of polymers.