Spectroscopic analysis of vibronic relaxation pathways in molecular spin qubit $[$Ho(W$_5$O$_{18}$)$_2]^{9-}$: sparse spectra are key

Abstract

Molecular vibrations play a key role in magnetic relaxation processes of molecular spin qubits as they couple to spin states, leading to the loss of quantum information.Direct experimental determination of vibronic coupling is crucial to understand and control the spin dynamics of these nano-objects, which represent the limit of miniaturization for quantum devices. Herein, we measure the vibrational properties of the molecular spin qubit Na 9 [Ho(W 5 O 18 ) 2 ]•35H 2 O by means of magneto-infrared spectroscopy.Our results allow us to unravel the vibrational decoherence pathways in combination with ab initio calculations including vibronic coupling. We observe field-induced spectral changes near 63 and 370 cm −1 that are modeled in terms of f -manifold crystal