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Wyświetlanie 1-7 z 7
Tytuł:
Application of the Package SIESTA to Linear Models of a Molecular Chromium-Based Ring
Autorzy:
Ślusarski, T.
Brzostowski, B.
Tomecka, D.
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1534920.pdf
Data publikacji:
2010-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
71.15.Mb
73.22.-f
75.30.Et
Opis:
We investigate for the first time the electronic and magnetic properties of the linear models of $Cr_8F_8(Piv)_{16}$ molecular ring using the SIESTA package. In the first step the proper values of the SIESTA parameters and the optimal basis set needed for the convergence of the total energy are established. Next the estimates of the magnetic coupling J confirming the previous density functional theory calculations are presented.
Źródło:
Acta Physica Polonica A; 2010, 118, 5; 967-968
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DFT Study of Octanuclear Molecular Chromium-Based Ring Using New Pseudopotential Parameters
Autorzy:
Brzostowski, B.
Ślusarski, T.
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1427181.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
71.15.Mb
73.22.-f
75.30.Et
Opis:
We present a comprehensive study of magnetic properties of $Cr_8F_8(Piv)_{16}$ molecular ring (in short Cr8) using the package SIESTA with several choices of chromium pseudopotential parameters. We use generalized gradient approximation to investigate properties of Cr8 ring approximated by replacing the pivallic group by H atoms (hydrogen saturation). For different choice of chromium pseudopotential we examine the electronic and magnetic properties of Cr8 molecule. We compare highest occupied molecular orbital and the lowest unoccupied molecular orbital gaps for both spin channels, magnetic moments, and exchange interaction parameter J. The influence of pseudopotential parameters on obtained results is discussed. Finally our results are compared with other theoretical approaches and experimental data.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1115-1117
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DFT and Falicov-Kimball Model Approach to $Cr_{9}$ Molecular Ring
Autorzy:
Brzostowski, B.
Wojciechowski, M.
Lemański, R.
Kamieniarz, G.
Timco, G.
Tuna, F.
Winpenny, R.
Powiązania:
https://bibliotekanauki.pl/articles/1368686.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
71.15.Mb
73.22.-f
75.30.Et
Opis:
Based on density functional theory (DFT) calculations, we present electronic and magnetic properties of nanometallic homo-nuclear chromium-based molecular rings $Cr_{9}F_{9}Cl_{2}(O_{2}C-C(CH_{3})_{3})_{17}$ recently synthesized. The magnetic moments are calculated, the spin density maps are discussed and the exchange interaction parameter is extracted. The complementary studies are carried out using the Falicov-Kimball model which reproduces very well the energy levels determined by different magnetic broken symmetry configurations obtained by DFT.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 270-271
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Advantages of the DFT Augmented Symmetry Approach to Simulations of the Chromium-Based Ring Cr₈ within B3LYP Functional
Autorzy:
Brzostowski, B.
Wojciechowski, M.
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1030669.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
71.15.Mb
73.22.-f
75.30.Et
31.15.E
Opis:
The DFT estimates of magnetic couplings in molecular nanomagnets are computationally demanding and their values have not achieved the satisfactory accuracy in spite of a lot of effort. We concentrate here on comprehensive tests for predictions of the recently proposed augmented symmetry approach aiming at reducing the computational complexity of the DFT calculations which is particularly important for the Wien2k code. Using the B3LYP functional, we demonstrate the numerical stability of magnetic couplings, magnetic moments and the HOMO-LUMO gaps, changing the fraction of exact exchange α. We reach the significant gain in the computing time without a loss in the accuracy of the final results with respect to those obtained by the standard PBE approach. We conclude that the value α=0.25 leads to best estimation of magnetic couplings for hybrid functionals within Wien2k.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 591-593
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Study of Magnetic Molecules Containing Cr₉ Chromium-Based Rings within Density Functional Theory
Autorzy:
Brzostowski, B.
Wojciechowski, M.
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1032265.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
71.15.Mb
73.22.-f
75.30.Et
31.15.E-
Opis:
We examine the electronic and magnetic properties of three frustrated Cr₉ molecules with a single bond defect using density functional theory method. Five non-equivalent broken-symmetry spin configurations with S=±3/2 for Cr are considered, the corresponding differences between the total energies are calculated and the exchange interaction parameters J extracted using different scenarios. We find that the couplings for all molecules are antiferrimagnetic. We also estimate the fundamental gaps and in addition, the high occupied molecular orbitals and low occupied molecular orbitals are plotted and discussed.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 961-963
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DFT Estimation of Exchange Coupling Constant of Cr₈ Molecular Ring using the Hybrid Functional B3LYP
Autorzy:
Wojciechowski, M.
Brzostowski, B.
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1386209.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
71.15.Mb
73.22.-f
75.30.Et
31.15.E-
71.10.-w
Opis:
A study of electronic and magnetic properties of an octametallic chromium-based homonuclear molecule Cr₈F₈(CO₂-C(CH₃)₃)₁₆ is presented, using density functional theory (DFT) approach and linearized augmented plane wave (LAPW) method with Perdew, Burke and Ernzerhof (PBE) and Becke 3-term correlation (B3LYP) functionals. The exchange coupling parameters between transition metals ions are extracted, taking into account two different (ferro- and antiferromagnetic) spin configurations. The value J=3.1 meV found for the hybrid B3LYP functional improves significantly the one obtained for the PBE functional and gives an evidence for the superiority of the former in simulation of molecular nanomgnets. Moreover, the hybrid functional yields excellent spin density localisation, an enhancement of the HOMO-LUMO gaps and the value 2.81 $μ_B$ of magnetic moment at the chromium centre in good agreement with experiment.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 407-409
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mapping of the DFT Spin Configuration Energies of Cr8Cd Molecular Ring onto the Energy Structure of Falicov-Kimball Model
Autorzy:
Wojciechowski, M.
Brzostowski, B.
Lemański, R.
Kamieniarz, G.
Powiązania:
https://bibliotekanauki.pl/articles/1386266.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Xx
71.15.Mb
73.22.-f
75.30.Et
31.15.E-
71.10.-w
Opis:
A comprehensive study of electronic and magnetic properties of a recently synthesized nonametalic chromium-based heteronuclear molecule Cr₈CdF₉(O₂C-C(CH₃)₃)₁₈ is presented, using DFT and Falicov-Kimball (FK) model approach. The magnetic moments are calculated and the spin charge density map is discussed. The exchange coupling parameters between transition metals ions are extracted, taking into account all the nonequivalent spin configurations. It is demonstrated that the energies of the spin configurations can be reproduced by the FK model with a set of parameters consistent with that for the parent Cr8 molecule. For molecular ring considered, the ground state corresponds to the antiferromagnetic configuration and the ferromagnetic configuration yields the highest energy.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 410-412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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