聚乙炔中双激子和两个单激子的稳态性质  

Static nature of biexciton and two single-excitons in polyacetylene

作　　者：孙书娟[1] 傅军[1] 姚钟瑜[1] 潘孟美[1] 

机构地区：[1]海南师范大学物理与电子工程学院,海南海口571158

出　　处：《河北科技大学学报》2011年第4期308-312,325,共6页Journal of Hebei University of Science and Technology

基　　金：海南师范大学青年教师基金资助项目(QN0803)

摘　　要：在Su-Schrieffer-Heeger(SSH)模型基础上,计入长程电子关联的影响,研究聚乙炔分子链中双激子态与2个单激子态的稳态性质,比较不同关联强度下激子的晶格位形、能级、电荷密度波、自旋密度波以及吸收谱线。结果表明:零电子关联下分子链中的2个单激子不能稳定存在;激子半径均随着关联强度的增加而减小;与双激子的2个能级精细结构相比,2个单激子的能隙出现4个精细结构;2类激子的电荷密度波、自旋密度波与吸收谱线均随关联强度变化,并呈现显著区别。以上结果为区分分子链中2类激子的行为提供了依据,结果显示在激子行为中必须考虑电子与其的关联性。Adding a extended Hubbard term to the SSH model for polyacetylene, we carried a self-consistent variation calculation on biexciton and two single-excitons in polyacetylene. The configuration,energy level, charge density wave, spin density wave and absorbance in the two systems are compared. Results show that the two single-excitons can not exist stablely without electronic correlation; radiuses of biexitons and single-excitons decrease as the electronic correlation increases;two single-excitons system has four energy levels in the energy gap, while biexciton system has only two; charge density wave, spin density wave and absorbance of the two systems all change according to the electronic correlation and with marked differences. The facts offer a criterion to distinguish the two kinds of exciton, and show that the electronic correlation must be considered in excitons behavior.

关 键 词：双激子 单激子 电子关联 能级 电荷密度波 自旋密度波 

分 类 号：O561.2[理学—原子与分子物理]