Comprehensive Studies of Magnetic Transitions and Spin–Phonon Couplings in the Tetrahedral Cobalt Complex Co(AsPh3)2I2

Moseley, Duncan H. and Liu, Zhiming and Bone, Alexandria N. and Stavretis, Shelby E. and Singh, Saurabh Kumar and et al, . (2022) Comprehensive Studies of Magnetic Transitions and Spin–Phonon Couplings in the Tetrahedral Cobalt Complex Co(AsPh3)2I2. Inorganic Chemistry, 61 (43). pp. 17123-17136. ISSN 0020-1669

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Abstract

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 (g modes) and far-IR-active phonons (u modes; space group P21/c, no. 14, Z = 4 for 1). 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. © 2022 American Chemical Society.

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IITH Creators:

IITH Creators	ORCiD
Singh, Saurabh Kumar	UNSPECIFIED

Item Type:

Article

Additional Information:

U.S. National Science Foundation (NSF; CHE-1900296 and CHE-2055499 to Z.-L.X.; DMR-2004732 to S.H.) and a Shull Wollan Center Graduate Research Fellowship (Z.L. and S.E.S.) are acknowledged for partial support of the research. K.T. thanks a U.S. Department of Navy HBCU/MI grant for support. K.R.D. gratefully acknowledges the National Science Foundation (CHE-1808779). Part of this work was performed at the National High Magnetic Field Laboratory which is supported by NSF Cooperative Agreement no. DMR-1644779 and the State of Florida. The authors acknowledge the support of the National Institute of Standards and Technology, U.S. Department of Commerce, in providing DCS used in this work. Additional neutron scattering experiments were conducted at the VISION beamline at ORNL’s Spallation Neutron Source, which is supported by the Scientific User Facilities Division, Office of Basic Energy Sciences (BES), U.S. Department of Energy (DOE), under Contract no. DEAC0500OR22725 with UT Battelle, LLC. The computing resources were made available through the VirtuES and the ICEMAN projects, funded by the Laboratory Directed Research and Development program and the Compute and Data Environment for Science (CADES) facility at ORNL. The authors thank Dr. Wei Zhou of the NIST Center for Neutron Research (NCNR) for help with the DCS experiment. S.K.S. thanks IIT Hyderabad and DST (SRG/2020/001323) for the startup research grant.

Subjects:

Chemistry

Divisions:

Department of Chemistry

Depositing User:

. LibTrainee 2021

Date Deposited:

11 Nov 2022 11:28

Last Modified:

11 Nov 2022 11:28

URI:

http://raiithold.iith.ac.in/id/eprint/11247