Quantum chemical study on hydrogen-bonding polymers using Elongation method

Ab initio quantum chemical calculation requires Order-N³ or Order-N⁴ method at the level of ab initio method. (N: the number of atomic orbitals) and thus, ab initio calculations are quite difficult to treat large organic systems. In this study, the elongation method that was developed in our laboratory to synthesize efficiently the electronic states of huge polymers was applied to hydrogen-bonding polymers. As a result, the calculation time for poly-glycine using the Elongation method is order-N. In addition, it was found the results obtained by the Elongation method were in excellent agreement with those by the conventional method. Moreover, the geometry optimization technique was incorporated into elongation method and applied to polyglycine, imidazole chain and so on.