Author, as appears in the article.: Wu, Jianfang; Sousa, Carmen; de Graaf, Coen;
Department: Química Física i Inorgànica
URV's Author/s: De Graaf, Cornelis
Keywords: Vibrational frequencies Transition-metal-complexes Transition temperature Systems State energetics Spin crossover Raman-spectroscopy Iron complexes Ir Fe(phen)(2)(ncs)(2) Equilibrium Dft Anharmonicity Accurate Ab-initio
Abstract: Spin crossover in transition metal complexes can be studied in great detail with computational chemistry. Over the years, the understanding has grown that the relative stability of high-spin (HS) versus low-spin (LS) states is a subtle balance of many factors that all need to be taken into account for a reliable description. Among the different contributions, the zero-point energy (ZPE) and the entropy play key roles. These quantities are usually calculated assuming a harmonic oscillator model for the molecular vibrations. We investigated the impact of including anharmonic corrections on the ZPE and the entropy and indirectly on the critical temperature of spin crossover. As test systems, we used a set of ten Fe(II) complexes and one Fe(III) complex, covering different coordination modes (mono-, bi-, and tri-dentate ligands), decreasing coordination number upon spin crossover, coordination by second- and third-row atoms, and changes in the oxidation state. The results show that the anharmonicity has a measurable effect, but it is in general rather small, and tendencies are not easily recognized. As a conclusion, we put forward that for high precision results, one should be aware of the anharmonic effects, but as long as computational chemistry is still struggling with other larger factors like the influence of the environment and the accurate determination of the electronic energy difference between HS and LS, the anharmonicity of the vibrational modes is a minor concern.
Thematic Areas: Materials science, multidisciplinary Materials chemistry Electronic, optical and magnetic materials Chemistry, physical Chemistry, inorganic & nuclear Chemistry (miscellaneous)
licence for use: https://creativecommons.org/licenses/by/3.0/es/
Author's mail: coen.degraaf@urv.cat
Author identifier: 0000-0001-8114-6658
Record's date: 2024-09-07
Papper version: info:eu-repo/semantics/publishedVersion
Link to the original source: https://www.mdpi.com/2312-7481/5/3/49
Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
Papper original source: Magnetochemistry. 5 (3):
APA: Wu, Jianfang; Sousa, Carmen; de Graaf, Coen; (2019). The Role of Vibrational Anharmonicity in the Computational Study of Thermal Spin Crossover. Magnetochemistry, 5(3), -. DOI: 10.3390/magnetochemistry5030049
Article's DOI: 10.3390/magnetochemistry5030049
Entity: Universitat Rovira i Virgili
Journal publication year: 2019
Publication Type: Journal Publications
Repositori URV