2026-04-18T05:57:45Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1952702025-12-04T21:40:31Zcom_2072_1057col_2072_478917col_2072_478933

00925njm 22002777a 4500 dc Amoza Dávila, Martín author Maxwell Villacorta, Lindley Andrés author Aliaga-Alcalde, Núria author Gómez Coca, Silvia author Ruiz Sabín, Eliseo author 2023-03-14T18:48:29Z 2023-03-14T18:48:29Z 2021-09-28 2023-03-14T18:48:29Z We report the spin dynamic properties of non-substituted ferrocenium complexes. Ferrocenium shows a field-induced single-molecule magnet behaviour in DMF solution while cobaltocene lacks slow spin relaxation neither in powder nor in solution. Multireference quantum mechanical calculations give a non-Aufbau orbital occupation for ferrocenium with small first excitation energy that agrees with the relatively large measured magnetic anisotropy for a transition metal S=1/2 system. The analysis of the spin relaxation shows an important participation of quantum tunnelling, Raman, direct and local-mode mechanisms which depend on temperature and the external field conditions. The calculation of spin-phonon coupling constants for the vibrational modes shows that the first vibrational mode, despite having a low spin-phonon constant, is the most efficient process for the spin relaxation at low temperatures. In such conditions, vibrational modes with higher spin-phonon coupling constants are not populated. Additionally, the vibrational energy of this first mode is in excellent agreement with the experimental fitted value obtained from the local-mode mechanism. Propietats magnètiques Fonons Ferromagnetisme Magnetic properties Phonons Ferromagnetism Spin-phonon coupling and slow-magnetic relaxation in pristine ferrocenium