过渡金属复合体中的自旋对称断裂和高精度合物使用基于精确交换能量密度的密度函数重新检查
Artur Wodyński1, Bryan Lauw1, Marc Reimann1
1Technische Universität Berlin, Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Straße des 17. Juni 135, Berlin, D-10623, Germany.
Journal of chemical theory and computation
|February 27, 2024
概括
密度函数理论的修正有效地减少了旋转对称性破坏,并改善了高精度合计算. 移位错误的纠正特别具有影响力,提高了复合物的准确性.
科学领域:
- 计算化学计算化学
- 量子化学 是一个量子化学.
- 无机化学 无机化学 有机化学
背景情况:
- 精确计算高精密合物 (HFC) 对于理解单核复合物至关重要.
- 之前的研究在混合函数中发现了旋转对称性破坏 (SSB),影响了HFC预测.
- 移位错误 (DE) 和强烈的相关效应导致密度函数理论 (DFT) 计算中的不准确性.
研究的目的:
- 用先进的DFT方法分析单核复合体中的旋转对称性破坏 (SSB) 和高精密合物 (HFC).
- 评估强相关性校正局部杂交 (scLHs) 和范围分离的局部杂交 (scRSLHs) 在缓解SSB和DE方面的有效性.
- 调查移位错误 (DE) 和强相关性 (sc) 校正对价值旋极化 (VSSP) 和HFCs的影响.
主要方法:
- 利用各种强相关性校正局部杂交物 (scLHs) 和强相关性校正范围分离局部杂交物 (scRSLHs).
- 应用对局部混合函数 (LMF) 的纠正,以解决移位错误 (DE).
- 检查的具体复合物:[Mn(CN) 4) 2-,MnO3,[Mn(CN) 4N]-,和[Mn(CN) 5NO]2- (带有集群嵌入).
主要成果:
- 无论是DE-校正和sc-校正术语都显著降低了SSB,并改善了双极HFCs.
- 发现DE校正比sc校正更有效.
- 通过在金属中心附近增强精确交换 (EXX) 添加剂,降低旋转密度外定位,DE校正降低VSSP.
- sc校正通过局部减少对联体原子的EXX添加剂来减少VSSP和SSB.
- 分析了scLHs和scRSLHs对同位素Mn HFCs的性能,包括核心旋极化.
结论:
- 具有DE和sc校正的高级DFT函数为计算Mn HFC提供了更高的准确性.
- 在缓解SSB和纠正复合体中的HFC方面,DE校正特别有效.
- 了解旋转密度移位和VSSP是改进过渡金属系统的DFT方法的关键.
更多相关视频
08:04Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
8.4K
09:06Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope
Published on: March 24, 2019
8.1K
相关概念视频
02:42Valence Bond Theory
8.6K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
8.6K
01:08Spin–Spin Coupling Constant: Overview
923
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
923
01:17Spin–Spin Coupling: One-Bond Coupling
973
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
973
03:02Colors and Magnetism
11.7K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
11.7K
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
1.0K
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
1.0K
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
1.0K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.0K