Dynamics of Polarons and Bipolarons with Interchain Coupling in Conjugated Polymers CLEBER DA SILVA PINHEIRO, GERALDO MAGELA E SILVA Institute of Physics, University of Brası ´lia, 70.910-900 Brası ´lia, DF, Brazil Received 17 November 2001; accepted 6 April 2003 Published online 00 Month 0000 in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/qua.10666 ABSTRACT: The interchain and interactions of two parallel chains are studied numerically through the dynamics of charged polaron and bipolaron in the presence of an electric field by using the Pariser–Parr–Pople model combined with the Su–Schrieffer–Heeger model. The electron–lattice coupling and the Brazovskii–Kirova- type symmetry-breaking interaction are introduced in the current model. The electric field is introduced in terms of a time-dependent vector potential that is included in the Hamiltonian through a Peierls substitution of the phase factor to the transfer integral. The charge-transfer probability between charged polarons and bipolarons belonging to neighboring chains is determined by the numerical resolution of the equations of motion within the unrestricted Hartree–Fock approximation. The effects of confinement on the polaron and bipolaron motion are determined. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 95: 000 – 000, 2003 Key words: bipolarons; conjugated polymers; dynamics; polarons Introduction T he field of polymers in material sciences is considered a very promising field of research. These materials have attracted much attention from the academic community because of their special characteristics. These systems are a fundamental part of molecular electronic devices and new com- pounds [1–5]. In conjugated polymers, there is a representative class of conducting polymers exhibiting quasi– one- dimensional conductivity. A number of peculiar optical, magnetic, and transport properties [6 –11] have been observed in these materials. It is very difficult to interpret these properties within the conventional semiconductor model. Meanwhile, the concept of nonlinear excitations—such as soli- tons, polarons, and bipolarons—turns out to be very successful in describing these striking phe- nomena. They are considered to play essential roles in the charge-transport mechanism. There are sev- eral theoretical studies on the dynamic of such de- Correspondence to: G. M. e Silva; e-mail: magela@fis.unb.br Contract grant sponsor: Brazilian National Research Council. International Journal of Quantum Chemistry, Vol 95, 000 – 000 (2003) © 2003 Wiley Periodicals, Inc. tapraid5/qz-qua/qz-qua/qz2703/qz0610-03a royerl S=6 6/6/03 8:27 Art: QCX11 Input-css(css)