Role of Long-Range Interaction in Photoinduced Spin-State Transitions in Spin-Crossover Complexes
Role of Long-Range Interaction in Photoinduced Spin-State Transitions in Spin-Crossover Complexes
复制标题
长程相互作用在自旋交叉复合物光致自旋态跃迁中的作用
DOI：
10.1143/jpsj.68.2164
复制
发表时间：
1999
影响因子：
1.7
通讯作者：
T. Ogawa
中科院分区：
文献类型：
--
作者：
K. Koshino;T. Ogawa
我们从理论上解释了自旋交叉配合物中光诱导低自旋→高自旋转变的特点，如激发光强度的阈值行为和潜伏期的存在。我们的研究是基于一个模型，其中一个单一的配合物是由两个电子状态和呼吸振荡模式描述的配合物之间的远程相互作用。作为自旋跃迁过程，我们考虑了LS→HS光激发过程和HS→LS非辐射衰变过程。后一过程的速率对晶体中的LS分数很敏感，因为HS→LS衰变的势垒依赖于配合物之间的远程相互作用的LS分数；随着LS分数的减小，亚稳HS态的寿命变长。这种敏感性导致LS分数的非线性时间演化，这与实验结果相吻合。
We explain theoretically the peculiarities of photoinduced low-spin (LS)→high-spin (HS) transitions in spin-crossover complexes, such as the threshold behavior in the excitation light intensity for phase conversion and the existence of the incubation period. Our investigation is based on a model where a single complex is described by the two electronic states and the breathing oscillation mode with the long-range interaction among the complexes. As the spin transition processes, we take into account the LS→HS photoexcitation process and the HS→LS nonradiative decay process. The rate for the latter process is sensitive to the LS fraction in the crystal because the potential barrier for the HS→LS decay is dependent on the LS fraction through the long-range interaction among the complexes; the lifetime of the metastable HS state becomes longer as the LS fraction decreases. Such sensitivity leads to the nonlinear temporal evolution for the LS fraction, which coincides with the experimental results.