The pathway toward the tailored synthesis of materials starts with precise characterization of the conformational properties and dynamics of individual molecules. Electron spin resonance based scanning tunneling microscopy can potentially address molecular structure with unprecedented resolution. Here, we determine the fine structure and geometry of an individual TiH molecule, utilizing a combination of a newly developed mK ESR-STM in a vector magnetic field and ab initio approaches. We demonstrate a strikingly large anisotropy of the g-tensor unusual for a spin doublet ground state, resulting from a non-trivial orbital angular momentum stemming from the molecular ground state. We quantify the relationship between the resultant fine structure, hindered rotational modes, and orbital excitations. Our model system provides new avenues to determine the structure and dynamics of individual molecules.
@article{arxiv.2007.01928,
title = {Quantifying the interplay between fine structure and geometry of an individual molecule on a surface},
author = {Manuel Steinbrecher and Werner M. J. van Weerdenburg and Etienne F. Walraven and Niels P. E. van Mullekom and Jan W. Gerritsen and Fabian D. Natterer and Danis I. Badrtdinov and Alexander N. Rudenko and Vladimir V. Mazurenko and Mikhail I. Katsnelson and Ad van der Avoird and Gerrit C. Groenenboom and Alexander A. Khajetoorians},
journal= {arXiv preprint arXiv:2007.01928},
year = {2021}
}