TY - JOUR
T1 - Comment on 'Polaron formation and symmetry breaking' by L. Zuppiroli et al. [Chem. Phys. Lett. 374 (2003) 7]
AU - Geskin, V. M.
AU - Cornil, J.
AU - Brédas, J. L.
N1 - Funding Information:
We are grateful to Profs. Zuppiroli and Bieber for helpful discussions and for making available their output files. The work in Mons has been partly supported by the Belgian Federal Government ‘Service des Affaires Scientifiques, Techniques et Culturelles (SSTC)’ in the framework of the ‘Pôle d’Attraction Interuniversitaire en Chimie Supramoléculaire et Catalyse Supramoléculaire (PAI 5/3)’, the Belgian National Fund for Scientific Research (FNRS/FRFC); The work at Georgia Tech is partly supported by the National Science Foundation (CHEM-0342321), the Office of Naval Research, and the IBM Shared University Research Program. J.C. is a research fellow of FNRS.
PY - 2005/2/14
Y1 - 2005/2/14
N2 - L. Zuppiroli et al. [Chem. Phys. Lett. 374 (2003) 7] have theoretically studied polaron formation in oligo(phenylene vinylene) radical ions. In particular, they obtained with the AM1/UHF method a stepwise increase of the relaxation energy with increasing chain length. In this Comment, we suggest that this result is likely to be an artifact. We argue that UHF is particularly inappropriate for studying energies of open-shell pi-conjugated systems because of inherent spin contamination leading to wrong molecular structures. We show that, within the AM1 methodology, relaxation energies are rather insensitive to chain length and discuss the origin of this behavior.
AB - L. Zuppiroli et al. [Chem. Phys. Lett. 374 (2003) 7] have theoretically studied polaron formation in oligo(phenylene vinylene) radical ions. In particular, they obtained with the AM1/UHF method a stepwise increase of the relaxation energy with increasing chain length. In this Comment, we suggest that this result is likely to be an artifact. We argue that UHF is particularly inappropriate for studying energies of open-shell pi-conjugated systems because of inherent spin contamination leading to wrong molecular structures. We show that, within the AM1 methodology, relaxation energies are rather insensitive to chain length and discuss the origin of this behavior.
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U2 - 10.1016/j.cplett.2004.12.101
DO - 10.1016/j.cplett.2004.12.101
M3 - Article
AN - SCOPUS:12844281190
VL - 403
SP - 228
EP - 231
JO - Chemical Physics Letters
JF - Chemical Physics Letters
SN - 0009-2614
IS - 1-3
ER -