Modeling of EPR parameters of copper(II) aqua complexes

Almeida, Katia Júlia de; Rinkevičius, Žilvinas; Hugosson, Håkan Wilhelm; Ferreira, A. C.; Ågren, Hans

doi:10.1016/j.chemphys.2006.11.015

Cited by 43 publications

(44 citation statements)

References 39 publications

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“…This is found to be essential for the quantitative reproduction of experimental values in the case of transition metal compounds and in particular for Cu 2+ complexes. 50,51 Although largely underestimated, the computed dipolar components make up the major part of the hyperfine coupling constants, in line with the fact that the unpaired electron lies mostly in a d orbital.…”

Section: Resultsmentioning

confidence: 91%

Copper impurities in bulk ZnO: A hybrid density functional study

Gallino

Valentin²

2011

The Journal of Chemical Physics

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Transition metal doping of ZnO is considered as a promising way to obtain a diluted magnetic semiconducting oxide. In this work we investigate copper doping of ZnO by means of density functional theory, using a hybrid exchange-correlation functional and a periodic approach with localized atomic basis functions. Isolated copper species, such as copper substitutional to zinc, Cu s , and Cu interstitial, Cu i , are analyzed in terms of transition energy levels and hyperfine coupling constants with reference to available spectroscopic data. We also examine the potential magnetic interaction between copper species, their interaction with oxygen vacancies, and the possibility of copper clustering. The relative stability of the various copper impurities considered in this study is finally compared on the basis of their formation energy at different oxygen chemical potentials and Fermi level values.

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Section: Resultsmentioning

confidence: 91%

Copper impurities in bulk ZnO: A hybrid density functional study

Gallino

Valentin²

2011

The Journal of Chemical Physics

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“…This was based on the comparison of the theoretical and experimental g-tensor values and hyperfine coupling constants (HFCC). The hyperfine coupling constant (A iso ) calculations of Almeida et al accounted for the non-relativistic Fermi contact term (A F C ), the spin-dipolar contributions (A SD ) [26,28] as well as for the spin-orbit contributions (A SO ) [29]. It has been shown [26,29] that the spinorbit contributions are crucial for the hyperfine coupling constant of transition metal complexes and they damp the non-relativistic Fermi contact term.…”

Section: Introductionmentioning

confidence: 97%

“…For completeness, Almeida et al [25] have performed a nonhybrid DFT CP dynamics of four-, five-and six-coordinated Cu 2+ complexes with a subsequent evaluation of the UVvis-NIR spectra using the obtained CP trajectories showing that the different coordination numbers have a considerable fingerprint impact on the UV and NIR regions of the spectrum, albeit the agreement with experiment in the vis region was unsatisfactory for all considered coordination numbers. Alternatively, Almeida et al [26] attempted to predict the coordination environment of Cu 2+ in water upon the calculated and measured [27] electron paramagnetic resonance (EPR) parameters. It was concluded [26] that the more favored coordination number in the first solvation sphere of Cu 2+ was five with square-pyramidal geometry.…”

Section: Introductionmentioning

confidence: 99%

“…Alternatively, Almeida et al [26] attempted to predict the coordination environment of Cu 2+ in water upon the calculated and measured [27] electron paramagnetic resonance (EPR) parameters. It was concluded [26] that the more favored coordination number in the first solvation sphere of Cu 2+ was five with square-pyramidal geometry. This was based on the comparison of the theoretical and experimental g-tensor values and hyperfine coupling constants (HFCC).…”

Section: Introductionmentioning

confidence: 99%

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Calculations of hyperfine coupling constant of copper(II) in aqueous environment. Finite temperature molecular dynamics and relativistic effects

et al. 2015

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The presented paper is focused on the calculation of hyperfine coupling constants (HFCC) of Cu (2+) ion in water environment. To simulate the conditions of the electron paramagnetic resonance (EPR) experiment in aqueous phase, molecular dynamics using the density functional theory (DFT) was employed. In total three different functionals (BLYP, B3LYP, M06) were employed for studying their suitability in describing coordination of Cu (2+) by water molecules. The system of our interest was composed of one Cu (2+) cation surrounded by a selected number (between thirty and fifty) of water molecules. Besides the non-relativistic HFCCs (Fermi contact terms) of Cu (2+) also the four-component relativistic HFCC calculations are presented. The importance of the proper evaluation of HFCCs, the inclusion of spin-orbit term, for Cu (2+) containing systems (Neese, J. Chem. Phys. 118, 3939 2003; Almeida et al., Chem. Phys. 332, 176 2007) is confirmed at the relativistic four-component level of theory.

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“…Experience suggests that at the level has been much activity in testing new density functionals in their application to radical EPR spectra. [33][34][35][36][37][38][39] There appears to be consensus that overall, hybrid density functionals yield the best predictions. Since the B3LYP functional [40][41][42] is already the "workhorse" of quantum chemistry, it is perhaps the most well established choice and its predictions for HFCs are often very good.…”

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confidence: 99%

Performance of modern density functional theory for the prediction of hyperfine structure: meta-GGA and double hybrid functionals

2007

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. Performance of modern density functional theory for the prediction of hyperfine structure: meta-GGA and double hybrid functionals. Molecular Physics, Taylor & Francis, 2008, 105 (15-16) AbstractThe performance of modern density functionals for the prediction of molecular hyperfine couplings is investigated for a series of small radicals and transition metal complexes. Besides the established BP86 (GGA) and B3LYP (hybrid) functionals we have tested two prototypical members of emerging classes of density functionals, namely the TPSS meta-GGA functional (together with its hybrid version TPSSh) and the B2PLYP double-hybrid functional. The latter is the first member of a 'fifth-rung' density functional that incorporates a fraction of orbital dependent nonlocal correlation energy estimated at the level of second order many-body perturbation theory. Since this approach is non-variational, it becomes necessary to derive and implement the so-called 'relaxed' densities in order to properly predict hyperfine couplings. The necessary formalism is described in some detail and the new method has been implemented into the ORCA electronic structure program. The results of extended test calculations reveal that TPSS is superior to BP86. The hybrid variant TPSSh is at least as accurate or better than the B3LYP functional and significantly superior to the nonhybrid TPSS variant. The B2PLYP functional also leads to accurate predictions and is a clear improvement for the difficult metal nucleus HFCs. However, it also showed a few significant outliers in the test set which points to a somewhat reduced stability in the method. The latter effect is largely attributed to the elevated fraction Hartree-Fock exchange (53%) and to some extent also to the perturbative correction.

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Modeling of EPR parameters of copper(II) aqua complexes

Cited by 43 publications

References 39 publications

Copper impurities in bulk ZnO: A hybrid density functional study

Copper impurities in bulk ZnO: A hybrid density functional study

Calculations of hyperfine coupling constant of copper(II) in aqueous environment. Finite temperature molecular dynamics and relativistic effects

Performance of modern density functional theory for the prediction of hyperfine structure: meta-GGA and double hybrid functionals

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