Molecular orbital theory for nonregular polymer chains: Distortions of an infinite chain of hydrogen molecules

A perturbative method is introduced for the theoretical study of lattice distortions in regular polymers. The method is applied to a chain of hydrogen atoms and an estimate of the error entailed in the first order expansion made from a comparison against direct calculations for special lattice distortions. These calculations suggest that the CNDO/2 molecular orbital method predicts the uniformly spaced chain of hydrogen molecules to be the most stable structure for this system.