Programming for the prediction of physico-chemical properties of polymer

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In order to predict physico - chemical properteis of polymers theoretically, two types of approaches have been proceedid. One of them is the approach form cluster calculations. In this cluster calculations, we developed what we called S - SCF method, by which we can predict the molecular structure in the crystal, and also the change in the dipolemoment at high pressure. The latter calculation is intimately connected with piezo - electricity.Another approach is the calculation of the electronic structure of aperiodic polymers by using the elongation method, which has been developed in our group. The elongation method is mimic to the polymerization reaction. That is, the electronic structure of aperiodic polymers is theoretically synthesized by adding a monomer to an oligomer. By this elongation method, we can obtained the electronic structure of aperiodic polymers with various length without increasing computation time. In the present, we are constructing the program package in which the elongation method is combined with various levels of molecular orbital method such as extended Huckel, CNDO/2 and MOPAC program which includes MNDO, PM3, and AM1. By using this program package, we can calculate the local density of states for aperiodic polymers, and can predict the hopping site between two polyacetylene chains. This shed light on the mechanism of electron conduction in guasi - one - dimensional conductor.