A Glimpse into the Ligand Field Theory from Density Functional Perspective
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Electronic structure of transition metal complexes are commonly rationalized within the Ligand Field Theory (LFT). In LFT the Hamiltonian is parameterized in terms of one-electron (LF) parameters and two-electron repulsion integrals (Racaha's parameters) within the manifold of d-electrons. These parameters are determined from a fit to some experimental spectrum. The main drawback of LFT is its empirical nature, thus being limited to a description of the data, and predictions are often restricted to a chemical intuition. To overcome this, hybrid methodology, which combines a multideterminant DFT-based method with LFT, so called LF-DFT, has been developed. At the same time, LF-DFT successfully tackles many shortcomings of standard DFT, including orbital degeneracy and excited states. It works by evaluating DFT energies of all the Slater determinants arising from a dn configuration of the transition-metal ion in the environment of coordinating ligands using Kohn−Sham orbitals. This set of... energies is then analyzed within a LF model to obtain variationally the energy and wave function of the ground and excited states. In doing so, both dynamical correlation (via exchange-correlation energy) and non-dynamical correlation (via LF CI) are considered. The quality of the LF-DFT for the calculations of d-d transitions is comparable to the high-level ab initio calculations, and in some cases, e.g. [CrF6]3-, [MnF6]2-, [Mn(H2O)6]2+, [Fe(H2O)6]3+ even outshines them. One of the main strengths of LF-DFT is accurate prediction of magnitude and sign of the Zero-Field Splitting (ZFS) parameters, as well as the orientation of the principal magnetic axes. In addition, we can pin-point the excitations that control the sign and magnitude of the ZFS parameters.Therefore, with a help from DFT based LF theory we can, hopefully, find a way to control the magnetic properties of transition metal complexes.
Keywords:
electronic structure / transition metal complexes / Ligand Field Theory / LF-DFT / DFT / magnetic properties / Zero-Field SplittingSource:
Book of abstracts - ECOSTBio: Sixth scientific workshop, March 30-31, 2017, Lisboa, Portugal, 2017, ST16-Publisher:
- Univ. Nova de Lisboa
- COST Action CM1305
Funding / projects:
- COST Action CM1305 - ECOSTBio (Explicit Control Over Spin-states in Technology and Biochemistry)
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IHTMTY - CONF AU - Zlatar, Matija AU - Gruden, Maja PY - 2017 UR - https://cer.ihtm.bg.ac.rs/handle/123456789/5927 AB - Electronic structure of transition metal complexes are commonly rationalized within the Ligand Field Theory (LFT). In LFT the Hamiltonian is parameterized in terms of one-electron (LF) parameters and two-electron repulsion integrals (Racaha's parameters) within the manifold of d-electrons. These parameters are determined from a fit to some experimental spectrum. The main drawback of LFT is its empirical nature, thus being limited to a description of the data, and predictions are often restricted to a chemical intuition. To overcome this, hybrid methodology, which combines a multideterminant DFT-based method with LFT, so called LF-DFT, has been developed. At the same time, LF-DFT successfully tackles many shortcomings of standard DFT, including orbital degeneracy and excited states. It works by evaluating DFT energies of all the Slater determinants arising from a dn configuration of the transition-metal ion in the environment of coordinating ligands using Kohn−Sham orbitals. This set of energies is then analyzed within a LF model to obtain variationally the energy and wave function of the ground and excited states. In doing so, both dynamical correlation (via exchange-correlation energy) and non-dynamical correlation (via LF CI) are considered. The quality of the LF-DFT for the calculations of d-d transitions is comparable to the high-level ab initio calculations, and in some cases, e.g. [CrF6]3-, [MnF6]2-, [Mn(H2O)6]2+, [Fe(H2O)6]3+ even outshines them. One of the main strengths of LF-DFT is accurate prediction of magnitude and sign of the Zero-Field Splitting (ZFS) parameters, as well as the orientation of the principal magnetic axes. In addition, we can pin-point the excitations that control the sign and magnitude of the ZFS parameters.Therefore, with a help from DFT based LF theory we can, hopefully, find a way to control the magnetic properties of transition metal complexes. PB - Univ. Nova de Lisboa PB - COST Action CM1305 C3 - Book of abstracts - ECOSTBio: Sixth scientific workshop, March 30-31, 2017, Lisboa, Portugal T1 - A Glimpse into the Ligand Field Theory from Density Functional Perspective SP - ST16 UR - https://hdl.handle.net/21.15107/rcub_cer_5927 ER -
@conference{ author = "Zlatar, Matija and Gruden, Maja", year = "2017", abstract = "Electronic structure of transition metal complexes are commonly rationalized within the Ligand Field Theory (LFT). In LFT the Hamiltonian is parameterized in terms of one-electron (LF) parameters and two-electron repulsion integrals (Racaha's parameters) within the manifold of d-electrons. These parameters are determined from a fit to some experimental spectrum. The main drawback of LFT is its empirical nature, thus being limited to a description of the data, and predictions are often restricted to a chemical intuition. To overcome this, hybrid methodology, which combines a multideterminant DFT-based method with LFT, so called LF-DFT, has been developed. At the same time, LF-DFT successfully tackles many shortcomings of standard DFT, including orbital degeneracy and excited states. It works by evaluating DFT energies of all the Slater determinants arising from a dn configuration of the transition-metal ion in the environment of coordinating ligands using Kohn−Sham orbitals. This set of energies is then analyzed within a LF model to obtain variationally the energy and wave function of the ground and excited states. In doing so, both dynamical correlation (via exchange-correlation energy) and non-dynamical correlation (via LF CI) are considered. The quality of the LF-DFT for the calculations of d-d transitions is comparable to the high-level ab initio calculations, and in some cases, e.g. [CrF6]3-, [MnF6]2-, [Mn(H2O)6]2+, [Fe(H2O)6]3+ even outshines them. One of the main strengths of LF-DFT is accurate prediction of magnitude and sign of the Zero-Field Splitting (ZFS) parameters, as well as the orientation of the principal magnetic axes. In addition, we can pin-point the excitations that control the sign and magnitude of the ZFS parameters.Therefore, with a help from DFT based LF theory we can, hopefully, find a way to control the magnetic properties of transition metal complexes.", publisher = "Univ. Nova de Lisboa, COST Action CM1305", journal = "Book of abstracts - ECOSTBio: Sixth scientific workshop, March 30-31, 2017, Lisboa, Portugal", title = "A Glimpse into the Ligand Field Theory from Density Functional Perspective", pages = "ST16", url = "https://hdl.handle.net/21.15107/rcub_cer_5927" }
Zlatar, M.,& Gruden, M.. (2017). A Glimpse into the Ligand Field Theory from Density Functional Perspective. in Book of abstracts - ECOSTBio: Sixth scientific workshop, March 30-31, 2017, Lisboa, Portugal Univ. Nova de Lisboa., ST16. https://hdl.handle.net/21.15107/rcub_cer_5927
Zlatar M, Gruden M. A Glimpse into the Ligand Field Theory from Density Functional Perspective. in Book of abstracts - ECOSTBio: Sixth scientific workshop, March 30-31, 2017, Lisboa, Portugal. 2017;:ST16. https://hdl.handle.net/21.15107/rcub_cer_5927 .
Zlatar, Matija, Gruden, Maja, "A Glimpse into the Ligand Field Theory from Density Functional Perspective" in Book of abstracts - ECOSTBio: Sixth scientific workshop, March 30-31, 2017, Lisboa, Portugal (2017):ST16, https://hdl.handle.net/21.15107/rcub_cer_5927 .