AN APPROACH TO THE AB-INITIO MOLECULAR-ORBITAL CALCULATION OF THE STABILIZING ENERGY ON POLYMER DOUBLE-STRANDED HELIX

An energy calculation procedure by using the ab initio molecular orbit al (MO) method was derived for the estimation of the stabilizing energ y of double-stranded helices on large oligomers and so polymers, altho ugh the usual ab initio MO method can not treat polymers. This procedu re was applied to the main-chain atom model of isotactic poly(methyl m ethacrylate) double-stranded helix. The results indicate that the calc ulated stabilizing energy on small oligomers is in good agreement with those by the usual method. Therefore, this procedure was found to be extensively applicable to the ab initio MO studies on the molecular-we ight dependency of the stabilizing energy of polymer double-stranded h elices.