Based on the Su-Schrieffer-Heeger(SSH) model extended to include the Brazovskii-Kirova symmetry breaking term,we investigate the scattering process between an injected polaron and an exciton in the presence of an electric field in a conjugated polymer chain.It is found that the polaron can always pass through the exciton in the presence of an external electric field.In contrast,the behavior of the exciton strongly depends on the electric field strength.If the field strength is greater than a critical value of about 3.0× 105 V/cm,the exciton does not move after the collision with the polaron.However,if the field strength is less than the critical value,the exciton has an obvious migration in the opposite direction of the moving polaron.This migration of exciton under weak electric fields is originally attributed to a slow scattering process with the charged polaron.%基于Su-Schrieffer-Heeger (SSH)模型并考虑到Brazovskii-Kirova对称破缺项,研究了共轭聚合物中注入极化子和激子在外电场下的散射过程.研究发现在外场作用下极化子总是能通过激子,而激子的运动行为则密切依赖于电场的强度.如果电场大于临界电场3.0×105 V/cm,那么激子与极化子散射后并不发生任何运动；然而当电场小于此临界值时,激子将在极化子运动的相反方向上有一个明显的位移.激子在弱电场下所发生的这种迁移运动,是由于同极化子发生了慢散射作用.
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