Density-functional study of the dimerization oftrans-polyacetylene

We report a self-consistent linear-combination-of-Gaussian-orbitals study of the dimerization of a single, infinite chain of trans-polyacetylene using the first-principles density-functional theory in the local-density approximation. As a result we get a dimerized ground state with a dimerization amplitude and stabilization energy of about 0.01 {} and 7 meV per dimer, respectively. The local exchange-correlation energy favors dimerization significantly. The total energy is found to be extremely sensitive to the k sampling at the Brillouin-zone boundaries for small dimerization amplitudes.