The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Paul M. Lahti - One of the best experts on this subject based on the ideXlab platform.
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Zero Field Splitting parameters of quintet 2 6 dinitrenopyridines
Journal of Physical Organic Chemistry, 2006Co-Authors: Sergei V. Chapyshev, Paul M. LahtiAbstract:The Zero Field Splitting parameters of two 2,6-dinitrenopyridines were estimated to be |D/hc| ≅ 0.19–0.20 cm−1 and |E/hc| ≅ 0.064–0.066 cm−1 by lineshape simulation of frozen solution X-band ESR spectra. This large ratio of |E/D| is consistent with a dominating dipolar interaction between the two nitrene units having a relative interaction vector angle of about 114°–116°. UB3LYP/6-31G* computations of 2,6-dinitrenopyridine predict a very similar interaction vector angle. These results are quite different from analogous results observed for meta-dinitrenobenzenes. The experimental Zero-Field Splitting (zfs) and computational results indicate that the ESR spectroscopy of 2,6-dinitrenopyridines are dominated by the one-center interactions between unpaired electrons on the nitrene units (the triplet mononitrene zfs), and the relative geometry of interaction between the mononitrenes caused by the molecular geometry of the dinitrenopyridine (the interaction vector angle). Copyright © 2006 John Wiley & Sons, Ltd.
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Zero‐Field Splitting parameters of quintet 2,6‐dinitrenopyridines
Journal of Physical Organic Chemistry, 2006Co-Authors: Sergei V. Chapyshev, Paul M. LahtiAbstract:The Zero Field Splitting parameters of two 2,6-dinitrenopyridines were estimated to be |D/hc| ≅ 0.19–0.20 cm−1 and |E/hc| ≅ 0.064–0.066 cm−1 by lineshape simulation of frozen solution X-band ESR spectra. This large ratio of |E/D| is consistent with a dominating dipolar interaction between the two nitrene units having a relative interaction vector angle of about 114°–116°. UB3LYP/6-31G* computations of 2,6-dinitrenopyridine predict a very similar interaction vector angle. These results are quite different from analogous results observed for meta-dinitrenobenzenes. The experimental Zero-Field Splitting (zfs) and computational results indicate that the ESR spectroscopy of 2,6-dinitrenopyridines are dominated by the one-center interactions between unpaired electrons on the nitrene units (the triplet mononitrene zfs), and the relative geometry of interaction between the mononitrenes caused by the molecular geometry of the dinitrenopyridine (the interaction vector angle). Copyright © 2006 John Wiley & Sons, Ltd.
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Zero-Field Splitting of quintet conjugated dinitrenes: 2,6-biphenylenedinitrene
Tetrahedron Letters, 2003Co-Authors: Rajdeep Kalgutkar, Paul M. LahtiAbstract:Abstract 2,6-Diazidobiphenylene was synthesized and photolyzed in frozen matrix. The resulting electron spin resonance spectrum showed the formation of 2,6-biphenylenedinitrene as a quintet species with Zero Field Splitting (zfs) parameters ∣D/hc∣=0.260±0.002 cm−1, ∣E/hc∣≤0.0005 cm−1. The zfs parameters are in excellent accord with dipolar models for a quintet state produced by interaction between triplet state nitrene sites.
Willem Van Den Heuvel - One of the best experts on this subject based on the ideXlab platform.
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communication paramagnetic nmr chemical shift in a spin state subject to Zero Field Splitting
Journal of Chemical Physics, 2013Co-Authors: Alessandro Soncini, Willem Van Den HeuvelAbstract:We derive a general formula for the paramagnetic NMR nuclear shielding tensor of an open-shell molecule in a pure spin state, subject to a Zero-Field Splitting (ZFS). Our findings are in contradiction with a previous proposal. We present a simple application of the newly derived formula to the case of a triplet ground state split by an easy-plane ZFS spin Hamiltonian. When kT is much smaller than the ZFS gap, thus a single non-degenerate level is thermally populated, our approach correctly predicts a temperature-independent paramagnetic shift, while the previous theory leads to a Curie temperature dependence.
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paramagnetic nmr chemical shift in a spin state subject to Zero Field Splitting
arXiv: Chemical Physics, 2012Co-Authors: Alessandro Soncini, Willem Van Den HeuvelAbstract:We derive a general formula for the paramagnetic NMR nuclear shielding tensor of an open-shell molecule in a pure spin state, subject to a Zero-Field Splitting (ZFS). Our findings are in contradiction with a previous proposal. We present a simple application of the newly derived formula to the case of a triplet ground state split by an easy-plane ZFS spin Hamiltonian. When $kT$ is much smaller than the ZFS gap, thus a single non-degenerate level is thermally populated, our approach correctly predicts a temperature-independent paramagnetic shift, while the previous theory leads to a Curie temperature dependence.
Qun Wei - One of the best experts on this subject based on the ideXlab platform.
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Analytical Investigations of Spin-Spin, Spin-Other-Orbit and Combined Mechanisms of Zero-Field Splitting for 3d 3 Ions at Trigonal Symmetry
Zeitschrift für Naturforschung A, 2009Co-Authors: Qun WeiAbstract:A new method of obtaining approximate analytical expressions of Zero-Field Splitting (ZFS) has been proposed. By analyzing the magnetic interaction mechanisms which affect the properties of ZFS of ground A2 state for 3d3 ions at trigonal symmetry, and comparing with the calculated results of complete diagonalization method, the approximate analytical expressions of the contribution to Zero-Field Splitting of A2 state from spin-spin (SS), spin-other-orbit (SOO), and combined mechanisms have been obtained. Also the applicability of these approximate analytical expressions has been analyzed. It is shown that the approximate analytical expressions are suitable in a wide crystal Field parameters range.
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Zero-Field Splitting of 4T2 term for 3d3 ions in tetragonal symmetry
Pramana, 2009Co-Authors: Qun WeiAbstract:By taking into account slight interactions, i.e. spin-spin, spin-other-orbit and orbit-orbit interactions, in addition to spin-orbit interaction, the Zero-Field Splitting of 4T2 state for 3d3 ions at tetragonal symmetry has been studied. The convergence of the approximation perturbation formula of 4T2 state for 3d3 ions at tetragonal symmetry has been investigated, and the contributions to Zero-Field Splitting arising from magnetic interaction and tetragonal crystal Field are discussed. It is found that there exists combined mechanism between magnetic interactions and tetragonal crystal Field.
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Theoretical investigations of Zero-Field Splitting of excited states for 3d3 ions in trigonal crystal Fields.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2006Co-Authors: Qun Wei, Zi-yuan Yang, Canjun WangAbstract:Abstract By taking into account slight interactions, i.e. spin–spin, spin–other-orbit and orbit–orbit interactions, in addition to spin–orbit interaction, the Zero-Field Splitting of ground state and low excited states and g factors of ZnGa2O4:Cr3+ crystal have been interpreted systematically. And the contributions to Zero-Field Splitting arising from slight magnetic interaction and trigonal crystal Field are investigated. It is found that there exist combined mechanism between magnetic interactions and trigonal crystal Field.
Canjun Wang - One of the best experts on this subject based on the ideXlab platform.
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Theoretical investigations of Zero-Field Splitting of excited states for 3d3 ions in trigonal crystal Fields.
Spectrochimica acta. Part A Molecular and biomolecular spectroscopy, 2006Co-Authors: Qun Wei, Zi-yuan Yang, Canjun WangAbstract:Abstract By taking into account slight interactions, i.e. spin–spin, spin–other-orbit and orbit–orbit interactions, in addition to spin–orbit interaction, the Zero-Field Splitting of ground state and low excited states and g factors of ZnGa2O4:Cr3+ crystal have been interpreted systematically. And the contributions to Zero-Field Splitting arising from slight magnetic interaction and trigonal crystal Field are investigated. It is found that there exist combined mechanism between magnetic interactions and trigonal crystal Field.
Alessandro Soncini - One of the best experts on this subject based on the ideXlab platform.
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communication paramagnetic nmr chemical shift in a spin state subject to Zero Field Splitting
Journal of Chemical Physics, 2013Co-Authors: Alessandro Soncini, Willem Van Den HeuvelAbstract:We derive a general formula for the paramagnetic NMR nuclear shielding tensor of an open-shell molecule in a pure spin state, subject to a Zero-Field Splitting (ZFS). Our findings are in contradiction with a previous proposal. We present a simple application of the newly derived formula to the case of a triplet ground state split by an easy-plane ZFS spin Hamiltonian. When kT is much smaller than the ZFS gap, thus a single non-degenerate level is thermally populated, our approach correctly predicts a temperature-independent paramagnetic shift, while the previous theory leads to a Curie temperature dependence.
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paramagnetic nmr chemical shift in a spin state subject to Zero Field Splitting
arXiv: Chemical Physics, 2012Co-Authors: Alessandro Soncini, Willem Van Den HeuvelAbstract:We derive a general formula for the paramagnetic NMR nuclear shielding tensor of an open-shell molecule in a pure spin state, subject to a Zero-Field Splitting (ZFS). Our findings are in contradiction with a previous proposal. We present a simple application of the newly derived formula to the case of a triplet ground state split by an easy-plane ZFS spin Hamiltonian. When $kT$ is much smaller than the ZFS gap, thus a single non-degenerate level is thermally populated, our approach correctly predicts a temperature-independent paramagnetic shift, while the previous theory leads to a Curie temperature dependence.