The calculation of the thermal dependency of the magnetic susceptibility in extended systems with ab initio electronic structure parameters
The thesis studies the magnetic coupling in systems of different dimensionality, by using multireference methods. The aim of the work is to determine macroscopic properties such as the thermal dependency of magnetic susceptibility, from the calculated magnetic exchange constant J. This microscopic p...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2011 |
| País: | España |
| Institución: | Universitat Rovira i virgili (URV) |
| Repositorio: | Repositori Institucional de la Universitat Rovira i Virgili |
| OAI Identifier: | oai:urv.cat:TDX:908 |
| Acceso en línea: | https://hdl.handle.net/20.500.11797/TDX908 http://hdl.handle.net/10803/31934 |
| Access Level: | acceso abierto |
| Palabra clave: | 544 - Química física 54 - Química |
| Sumario: | The thesis studies the magnetic coupling in systems of different dimensionality, by using multireference methods. The aim of the work is to determine macroscopic properties such as the thermal dependency of magnetic susceptibility, from the calculated magnetic exchange constant J. This microscopic parameter quantifies the magnetic interaction between two magnetic sites and can be extracted from the experimental susceptibility curve in finite systems. However this extraction is not possible in extended magnetic systems such as chains or 2D-layers. The strategy followed consists in calculating J in small clusters and in simulating the extended systems by introducing the calculated J in the Heisenberg Hamiltonian of 8 to 16 site models. From the spectrum, the thermal dependency of the magnetic susceptibility is the calculated. When compared to the experimental one, this curve gives a quantification of the magnetic interactions of the studied materials at the microscopic level. We have studied different types of extended systems such as chains and hexagonal lattices, where the magnetic sites are transition metal ions. |
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