Hybrid Methods of Molecular Modeling

Tchougréeff, Andreì L.; TchougrÃ©eff, Andrei L.

doi:10.1007/978-1-4020-8189-7

Cited by 31 publications

(24 citation statements)

References 22 publications

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“…21,22 The solution 23 is given by the concerted usage of McWeeny's group-function formalism 24 and Loẅdin's partition technique 25 as described in reviews 26,27 and in a monograph. 28 This combination provides a new concept of semiempirism in quantum chemistry: taking the form of the wave function on the basis of observable electronic groups such as d-shells, π-systems, two-center bonds, and so onchromophores, as we will call them in the sequel in a somewhat generalized sensewhich characterize the molecular class and which effective Hamiltonians need to be parametrized. The effective Hamiltonian technique serves as a formal implementation of the above concept.…”

Section: Introductionmentioning

confidence: 99%

Effective Hamiltonian Crystal Field As Applied to Magnetic Exchange Parameters in μ-Oxo-Bridged Cr(III) Dimers

Tchougréeff

Dronskowski

2013

J. Phys. Chem. A

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The calculation of the 3d-intrashell excitations in coordination compounds by means of the Effective Hamiltonian Crystal Field (EHCF) method is generalized to their polynuclear analogues to properly describe several open d-shells and their magnetic interactions. This challenge requires improving the precision of ca. 1000 cm −1 to ca. 100 cm −1 characteristic for the spin-reorientation energies. The method follows the successful EHCF paradigm, namely, the concerted usage of McWeeny's group-function approximation and Loẅdin's partitioning technique, for an effective description of the multicenter d-systems. The novel approach is implemented in the MagAıxTic package and validated against a series of binuclear complexes of Cr(III) featuring μ-oxygen superexchange paths. The trends in the compound series in terms of exchange constants are correctly reproduced, despite differing details of composition and structure, and the numerical results agree by order of magnitude with available experimental data and other theoretical methods.

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Section: Introductionmentioning

confidence: 99%

Effective Hamiltonian Crystal Field As Applied to Magnetic Exchange Parameters in μ-Oxo-Bridged Cr(III) Dimers

Tchougréeff

Dronskowski

2013

J. Phys. Chem. A

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“…They recently had been applied to assessment of exchange integrals in diiron complexes . Obviously, such approaches are in principle capable to reproduce whatever characteristics of molecules “in the infinite limit.” For example, only the infinite DMRG summation yields the adequate result for diiron complex. However, this achievement must be considered as an accidental one since analogous treatment applied to dichromium complex results in not more than 60% of the experimental amount.…”

Section: Latest Applicationsmentioning

confidence: 99%

“…The physical fact, however, is that solutions of Eqs. and in different areas of the

{Z_{α}, {\vec{R}}_{α}}

parameter space are very different in nature . Thus the convergence by itself does not guarantee the success, since the required expansion can become too long.…”

Section: Introductionmentioning

confidence: 99%

Effective hamiltonian crystal field: Present status and applications to iron compounds

Tchougréeff

Soudackov

Leusen

et al. 2015

Int J of Quantum Chemistry

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“…35 The AMM values of any element vary with the geometry of each particular atomic position in various zeolites and could be hardly compared without the common coordinate space [eqs. (3)- (4)] introduced by the CC method.…”

Section: Approximation Of the Atomic Multipole Momentsmentioning

confidence: 99%

Point atomic multipole moments for simulation of electrostatic potential and field in all‐siliceous zeolites

Larin¹

2011

J Comput Chem

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Calibration method of atomic multipole moments (AMMs) is presented with respect to geometries of all-siliceous zeolite models obtained with X-ray diffraction (XRD) methods. Mulliken atomic charges and AMMs are calculated for all-siliceous types possessing small size elementary unit cells at the hybrid density functional theory (DFT) (B3LYP) and general gradient approximation (GGA) Perdew-Burke-Ernzerhof (PBE) levels and then used to fit the dependences versus geometry variables for the Mulliken charges and versus special coordinate for the AMMs. Fitted and exact charges and AMMs are used to compute electrostatic potential (EP) and electric field (EF) for all-siliceous zeolites with CRYSTAL. A possibility of application of the point AMMs to quantum mechanical/molecular mechanics computations or classic simulation of physical adsorption is evaluated. The considered models expand over wide range of structural parameters and could be applied even to amorphous all-siliceous systems.

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Hybrid Methods of Molecular Modeling

Cited by 31 publications

References 22 publications

Effective Hamiltonian Crystal Field As Applied to Magnetic Exchange Parameters in μ-Oxo-Bridged Cr(III) Dimers

Effective Hamiltonian Crystal Field As Applied to Magnetic Exchange Parameters in μ-Oxo-Bridged Cr(III) Dimers

Effective hamiltonian crystal field: Present status and applications to iron compounds

Point atomic multipole moments for simulation of electrostatic potential and field in all‐siliceous zeolites

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