Bulk properties from finite-cluster calculations. VII. Accurate ab initio calculations on the Peierls distortions in polyacene

Abstract

Properties of both the undistorted and the Peierls‐distorted polyacene polymers are obtained with the help of Padé approximants from the results of HF/6–311G** and MP2/6–311G** electronic structure calculations on the respective finite clusters. At the Hartree–Fock level, the (E)‐distorted structure has the lowest energy per unit cell. At the correlated level, the undistorted structure is slightly favored. The C–C bond alternation is found to be more pronounced in the (Z)‐distorted isomer than in the (E)‐distorted one.