【摘要】 在一维反铁磁体CsMnCl₃·2H₂O中,用D₂O代替其中的结晶水之后,对于⁴T₁→⁶A₁激子跃迁,观察到三种明显的效应:激子线红移18cm^-1;激子讯号增强近一个数量级;激子寿命由0.58ms变为9.2ms,增加15倍。这后一种效应在文献中尚未见报道,它说明这种同位素替代使振动猝灭受到很大的减弱。利用多声子辐射和无辐射跃迁理论,讨论了实验结果。分析表明,同位素替代改变了晶格振动的频谱,对无辐射跃迁产生很大的影响。电声子耦合强度没有明显的变化,黄昆-Rhys因子基本保持常数。卷入多声子辐射跃迁的声子模和卷入无辐射跃迁的声子模是不相同的,其能量有相当大的差别:前一种声子模与H₂O振动没有很大关系;而后一种声子模却与H₂O振动紧密相关。更多还原

【Abstract】 The exciton transition 4T1 →6A1 of Mn2+ ions in quasi one-dimensional antiferro-magnet CsMnCl3·2H20 is very weak in intensity with a shorter lifetime due to the vibration-queching. Replacing H2O by D2O), three important effects have been observed: the exciton line is shifted to the red by 18cm-1, the intensity of the exciton is increased by almost one order, the lifetime is lengthened from 0.58 ms to 9.2 ms. These facts show that the vibration-quenching has been weakened. The experimental results are analysed by means of the theory of multi-phonon radiative and non-radiative transitions. It has been shown that the isotope substitution changes the spectrum of lattice vibration, and brings forth a great influence on the non-radiative transition. The electronphonon coupling intensity does not show any obvious change, and the Huang-Rhys factor remains constant. The phonon modes involved in the multi-phonon radiative transition are different from those involved in the multi-phonon nonradiative process, their average energies are quite different from each other.更多还原