固体物理吸收与发射教学中费米黄金定则的应用  

Application of Fermi's golden rule in teaching of absorption and emission of solid physics

作　　者：胡焱清 HU Yan-qing(School of Materials Science and Engineering,Suzhou University of Science and Technology,Suzhou,Jiangsu 215009,China)

机构地区：[1]苏州科技大学材料科学与工程学院,江苏苏州215009

出　　处：《大学物理》2024年第5期9-12,21,共5页College Physics

基　　金：江苏省自然科学基金(BK20211337);江苏省“双创博士”科研项目(JSSCBS20210718)资助。

摘　　要：费米黄金定则是描述一个系统波函数由一个特征态变换为另一个特征态概率的理论,该理论可以很好地阐述固体发光材料的吸收和发射.然而费米黄金定则的推导过程比较复杂,学生对推导的结果不理解,这会影响后续的教学进度和整体的教学质量.本文回顾了费米黄金定则的推导过程,并基于该定则,推导出施主-受主系统电偶极子间的能量传递速率,证实电偶极子间的能量传递跟介电常数的平方和距离的六次方呈反比,该结果为调节电偶极子间的能量传递速率提供了理论依据.此外,根据费米黄金定则,建立了离子偶极子-原子偶极子能量传递模型,推导了发光中心离子偶极子-表面分子原子偶极子能量传递速率,阐明了发光中心激发态能量耗散机制,提出了增强发光中心发射效率的有效措施.这些应用举例能让学生更深入地理解费米黄金定则的物理意义.Fermi's golden rule is a theory describing the probability of wave function of a system changing from one characteristic state to another,which can well elaborate the absorption and emission of solid luminescent materials.However,the derivation process of Fermi's golden rule is relatively complex,and students do not understand the results of the derivation,which affects the follow-up teaching progress and the overall teaching quality.In this work,the derivation of the Fermi's golden rule formula is reviewed.Based on this rule,an energy transfer rate between electric dipoles of a donor-acceptor system is derived,which demonstrates that the energy transfer between the electric dipoles is inversely proportional to both the square of dielectric constant and the sixth power of coupling distance.This result provides a theoretical basis for regulating the energy transfer rate between electric dipoles.In addition,an ion dipole-atom dipole energy transfer model is established according to the Fermi's golden rule formula and their energy transfer rate is derived.The proposed theory clarifies the energy dissipation mechanism of excited states of emitting centers,and provides effective measures to enhance the emission efficiency.This application example enables students to better understand the physical meaning of the Fermi's golden rule.

关 键 词：费米黄金定则 电偶极子 固体物理 

分 类 号：O482[理学—固体物理]