一维反铁磁体二水CsMnCl3中激子的振动猝灭和黄昆-Rhys因子

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 关键词：

THE VIBRATION-QUENCHING OF THE EXCITON AND THE HUANG-RHYS FACTOR IN THE QUASI ONE-DIMENSIONAL ANTIFERROMAGNET CMC

The exciton transition ⁴T₁→⁶A₁ of Mn²⁺ ions in quasi one-dimensional antiferro-magnet CsMnCl₃·2H₂O 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.