title: Reverse polarization in charged pi-conjugated oligomers.
abstract: Single-photon excitation in a charged pi-conjugated oligomer is studied theoretically. An apparent reverse polarization is obtained through single-photon excitation, which is different from that obtained through a double-photon excitation. The polarizability is calculated and it is found that a maximum reverse polarization will appear at a suitable conjugation length. In addition, we indicate that the reverse polarization is a nonlinear behavior with the induced electric field. Effects of nondegenerate confinement and interchain interactions on the reverse polarization are also discussed.
authors.affiliation: School of Physics and Microelectronics, Shandong University, Jinan 250100, People's Republic of China.
authors.forename: Kun
authors.initials: K
authors.lastname: Gao
authors.forename: Xiao-jing
authors.initials: XJ
authors.lastname: Liu
authors.forename: De-sheng
authors.initials: DS
authors.lastname: Liu
authors.forename: Shi-jie
authors.initials: SJ
authors.lastname: Xie