@article{BoisKoerzdoerfer2016,
  author    = {Bois, Juliana and K{\"o}rzd{\"o}rfer, Thomas},
  title     = {0 How Bond Length Alternation and Thermal Disorder Affect the Optical Excitation Energies of pi-Conjugated Chains: A Combined Density Functional Theory and Molecular Dynamics Study},
  series = {Journal of chemical theory and computation},
  volume    = {12},
  journal   = {Journal of chemical theory and computation},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1549-9618},
  doi       = {10.1021/acs.jctc.5b01070},
  pages     = {1872 -- 1882},
  year      = {2016},
  abstract  = {We dissect the sources of error leading to inaccuracies in the description of the geometry and optical excitation energies of pi-conjugated polymers. While the ground-state bond length alternation is shown to be badly reproduced by standard functionals, the recently adapted functionals PBEh* and omega PBE* as well as the double hybrid functional XYGJ-OS manage to replicate results obtained at the CCSD(T) level. By analysis of the bond length alternation in the excited state, a sensitive dependence of the exciton localization on the long-range behavior of the functional and the amount of Hartree-Fock exchange present is shown. Introducing thermal disorder through molecular dynamics simulations allows the consideration of a range of thermally accessible configurations of each oligomer, including trans to cis rotations, which break the conjugation of the backbone. Thermal disorder has a considerable effect when combined with functionals that overestimate the delocalization of the excitation, such as B3LYP. For functionals with a larger amount of exact exchange such as our PBEh* and omega PBE*, however, the effect is small, as excitations are often localized enough to fit between twists in the chain.},
  language  = {en}
}