Latham, EdwardBowen, Alice M.Cox, NicholasChilton, Nicholas F.2025-07-082025-07-080020-1669ORCID:/0000-0002-7815-6115/work/189727469Bibtex:latham_inverse_2025WOS:001460235700001https://hdl.handle.net/1885/733766384The development of molecular quantum bits (qubits) for quantum information processing is a lofty goal. While many contemporary works investigate their potential for error correction, fault-tolerance, memories, etc., there is still a lack of experimental examples of molecular multiqubit sequences. Herein, we perform a theoretical investigation of spin Hamiltonian parameter space to identify molecules that could be used to implement a 4-level superdense coding algorithm that has the least stringent requirements for experimental implementation. To do so, we analyze the zero-field splitting (ZFS) Hamiltonian of an S = 3/2 spin system to determine its effectiveness as a molecular qudit capable of performing the superdense coding circuit with X-band pulsed electron paramagnetic resonance (EPR), accounting for realistic constraints imposed by EPR spectrometers. For an S = 3/2 system, the optimal ZFS parameters are |D| approximate to 0.115 cm-1 and |E| approximate to -0.0383 cm-1 (|E/D| approximate to 0.33 approaching the rhombic limit of 1/3), with a field around 160 mT. Our findings highlight the need to maximize the rhombicity of the spin Hamiltonian for four-level molecular qudits.We thank the Australian National University for providing the resources and support necessary for this research. AMB thanks the Royal Society and the EPSRC for a Dorothy Hodgkin fellowship (DH160004), The University of Manchester for a Dame Kathleen Ollerenshaw Fellowship, and the Royal Society of Chemistry and the Analytical Chemistry Trust Fund and the Community for Analytical and Measurement Science fellowship (CAMS Fellowship 2020 ACTF ref 600310/09).9enPublisher Copyright: © 2025 The Authors. Published by American Chemical Society.Electron Paramagnetic Resonance Spectroscopy2025-04-0410.1021/acs.inorgchem.5c00298105001928515