Moseley Duncan H, Liu Zhiming, Bone Alexandria N, Stavretis Shelby E, Singh Saurabh Kumar, Atanasov Mihail, Lu Zhengguang, Ozerov Mykhaylo, Thirunavukkuarasu Komalavalli, Cheng Yongqiang, Daemen Luke L, Lubert-Perquel Daphné, Smirnov Dmitry, Neese Frank, Ramirez-Cuesta A J, Hill Stephen, Dunbar Kim R, Xue Zi-Ling
Department of Chemistry, University of Tennessee, Knoxville, Tennessee37996, United States.
Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, 502285Sangareddy, Telangana, India.
Inorg Chem. 2022 Oct 31;61(43):17123-17136. doi: 10.1021/acs.inorgchem.2c02604. Epub 2022 Oct 20.
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(AsPh)I (), a reported single-molecule magnet (SMM). With applied field, the magnetic zero-field splitting (ZFS) peak (2') shifts to higher energies in each spectroscopy. INS placed the ZFS peak at 54 cm, 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 ( modes) and far-IR-active phonons ( modes; space group 2/, no. 14, = 4 for ). These couplings are fit using a simple avoided crossing model with coupling constants of ca. 1-2 cm. 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.
非弹性中子散射（INS）、远红外磁光谱（FIRMS）和拉曼磁光谱（RaMS）相结合，已被用于全面探测报道的单分子磁体（SMM）Co(AsPh)I中的磁激发。施加磁场时，每种光谱中磁零场分裂（ZFS）峰（2'）都会向更高能量移动。INS将ZFS峰置于54 cm处，变温（VT）和变磁场数据均揭示了这一点，其结果与远红外和拉曼研究结果吻合良好。FIRMS和RaMS还揭示了多个自旋 - 声子耦合的存在，表现为与相邻声子的避免交叉。这里，声子既指分子内振动，也指晶格振动。这些结果构成了一个罕见的例子，其中在拉曼活性（模式）和声子（模式；空间群2/，编号14，对于 = 4）的远红外活性声子中都观察到了自旋 - 声子耦合。使用耦合常数约为1 - 2 cm的简单避免交叉模型对这些耦合进行了拟合。综合光谱准确地确定了磁激发能级以及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结果比较良好，从而能够对模式及其对称性进行归属。电子计算阐明了该配合物中ZFS的性质。总结了在过渡金属配合物中确定ZFS和其他自旋哈密顿参数的不同技术的特点。
