jp062701+_si_001.pdf (70.7 kB)
Bond Length Alternation and Energy Band Gap of Polyyne
journal contribution
posted on 2006-08-10, 00:00 authored by Shujiang Yang, Miklos KerteszThe bond length alternation (BLA) and energy band gap of polyyne are investigated by various first-principles
theories, including Hartree−Fock, MP2, hybrid, and nonhybrid density functional theories. Both solid-state
calculations utilizing periodic boundary conditions on polymers and molecular quantum mechanical calculations
on extra-long oligomers were performed with consistent results. By validation on similar linear conjugated
polymers, polyacetylene and polydiacetylene, the combination of hybrid-DFT schemes, B3LYP//BHandHLYP
or B3LYP//KMLYP, is shown to give the best predictions for both geometry and band gap of polyyne based
on available experimental data. We conclude that the best estimate of the BLA of polyyne is about 0.13 Å
and that of the band gap is about 2.2 eV.