Comprehensive Studies of Magnetic Transitions and Spin–Phonon Couplings in the Tetrahedral Cobalt Complex Co(AsPh 3 ) 2 I 2
Comprehensive Studies of Magnetic Transitions and Spin–Phonon Couplings in the Tetrahedral Cobalt Complex Co(AsPh 3 ) 2 I 2
复制标题
四面体钴配合物Co(AsPh 3 ) 2 I 2 中磁跃迁和自旋声子耦合的综合研究
DOI：
10.1021/acs.inorgchem.2c02604
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发表时间：
2022
影响因子：
4.6
通讯作者：
Cheng, Yongqiang
中科院分区：
文献类型：
--
作者：
Moseley, Duncan H.;Liu, Zhiming;Bone, Alexandria N.;Stavretis, Shelby E.;Singh, Saurabh Kumar;Atanasov, Mihail;Lu, Zhengguang;Ozerov, Mykhaylo;Thirunavukkuarasu, Komalavalli;Cheng, Yongqiang
非弹性中子散射（INS）、远红外磁波谱（FIRMS）和拉曼磁波谱（RaMS）的结合被用于全面探测Co(AsPh3)2I2(1)中的磁激发，这是一种报道的单分子磁体（SMM）。随着外加磁场的增加，各光谱中磁场零场分裂（ZFS）峰（2D’）向高能量方向移动。根据变温（VT）和变磁场数据显示，INS将ZFS峰置于54 cm-1处，其结果与远红外和拉曼研究结果一致。firm和RaMS还揭示了多个自旋声子耦合的存在，以避免与邻近声子交叉。这里，声子指的是分子内振动和晶格振动。该结果构成了一个罕见的情况下，自旋声子耦合被观察到与拉曼主动（gmode）和远红外主动声子（umode）；空间群pp21 /c， no. 1。14，Z= 4(1)。这些耦合用一个简单的避免交叉模型拟合，耦合常数约为1-2 cm-1。组合光谱准确地确定了磁激发能级和磁激发与声子模式的相互作用。密度泛函理论（DFT）声子计算与INS比较好，允许分配模式和它们的对称性。电子计算阐明了复合材料中ZFS的性质。综述了测定过渡金属配合物中ZFS和其他自旋哈密顿参数的不同方法的特点。
A combination of inelastic neutron scattering (INS), far-IR magneto-spectroscopy (FIRMS), and Raman magneto-spectroscopy (RaMS) has been used to comprehensively probe magnetic excitations in Co(AsPh3)2I2(1), a reported single-molecule magnet (SMM). With applied field, the magnetic zero-field splitting (ZFS) peak (2D′) shifts to higher energies in each spectroscopy. INS placed the ZFS peak at 54 cm–1, as revealed by both variable-temperature (VT) and variable-magnetic-field data, giving results that agree well with those from both far-IR and Raman studies. Both FIRMS and RaMS also reveal the presence of multiple spin–phonon couplings as avoided crossings with neighboring phonons. Here, phonons refer to both intramolecular and lattice vibrations. The results constitute a rare case in which the spin–phonon couplings are observed with both Raman-active (gmodes) and far-IR-active phonons (umodes; space groupP21/c, no. 14,Z= 4 for1). These couplings are fit using a simple avoided crossing model with coupling constants of ca. 1–2 cm–1. The combined spectroscopies accurately determine the magnetic excited level and the interaction of the magnetic excitation with phonon modes. Density functional theory (DFT) phonon calculations compare well with INS, allowing for the assignment of the modes and their symmetries. Electronic calculations elucidate the nature of ZFS in the complex. Features of different techniques to determine ZFS and other spin-Hamiltonian parameters in transition-metal complexes are summarized.