A b i n i t i o studies on polymers. V. All-t r a n s-polyethylene

Abstract

The ab initio crystal orbital method has been applied to study the electronic ground state of an infinite polyethylene chain in the all‐trans conformation within the framework of the Hartree–Fock approximation. Gaussian basis sets of minimal and double zeta quality have been used to evaluate equilibrium geometry and longitudinal elastic modulus of this model system. A structure with r_CC = 2.952 bohr, r_CH = 2.082 bohr, ∢CCC = 112.2°, and ∢HCH = 107.4° has been found to be most stable and a longitudinal elastic modulus of 345 GPa is predicted. Basis set dependence and the influence of lattice sum truncations on the electronic band structure are thoroughly discussed. Calculations including polarization functions have subsequently been performed in order to obtain electronic band structure and density of states at a near Hartree–Fock limit quality.