Stochastic Liouville equation treatment of the electron paramagnetic resonance line shape of an S-state ion in solution
| Autor: | Robert B. Clarkson, Alain Borel, R. Linn Belford |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Zeeman effect
Chemistry Relaxation (NMR) Electron Spin Resonance Spectroscopy General Physics and Astronomy Electrons Gadolinium Spectral line law.invention Magnetic field Solutions symbols.namesake law Molecular vibration Quantum mechanics Cations symbols Quantum Theory Zeeman energy Spin Labels Physical and Theoretical Chemistry Electron paramagnetic resonance Spin (physics) Algorithms |
| Zdroj: | The Journal of chemical physics. 126(5) |
| ISSN: | 0021-9606 |
| Popis: | The current approaches used for the analysis of electron paramagnetic resonance spectra of Gd3+ complexes suffer from a number of drawbacks. Even the elaborate model of [Rast et al., J. Chem. Phys. 113, 8724 (2000)] where the electron spin relaxation is explained by the modulation of the zero-field splitting (ZFS), by molecular tumbling (the so called static contribution), and deformations (transient contribution), is only readily applicable within the validity range of the Redfield theory [Advances in Magnetic Resonance, edited by J.-S. Waugh (Academic, New York, 1965), Vol. 1, p. 1], that is, when the ZFS is small compared to the Zeeman energy and the rotational and vibrational modulations are fast compared to the relaxation time. Spin labels (nitroxides and transition metal complexes) have been studied for years in systems that violate these conditions. The theoretical framework commonly used in such studies is the stochastic Liouville equation (SLE). The authors shall show how the physical model of Rast et al. can be cast into the SLE formalism, paying special attention to the specific problems introduced by the [Uhlenbeck and Ornstein, Phys. Rev. 36, 823 (1930)] process used to model the transient ZFS. The resulting equations are very general and valid for arbitrary correlation times, magnetic field strength, electron spin S, or symmetry. The authors demonstrate the equivalence of the SLE approach with the Redfield approximation for two well-known Gd3+ complexes. |
| Databáze: | OpenAIRE |
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