Jove
Visualize
联系我们
JoVE
x logofacebook logolinkedin logoyoutube logo
关于 JoVE
概览领导团队博客JoVE 帮助中心
作者
出版流程编辑委员会范围与政策同行评审常见问题投稿
图书馆员
用户评价订阅访问资源图书馆顾问委员会常见问题
研究
JoVE JournalMethods CollectionsJoVE Encyclopedia of Experiments存档
教育
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab Manual教师资源中心教师网站
使用条款与条件
隐私政策
政策

相关概念视频

¹H NMR: Interpreting Distorted and Overlapping Signals01:02

¹H NMR: Interpreting Distorted and Overlapping Signals

1.5K
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...
1.5K
Spin–Spin Coupling Constant: Overview01:08

Spin–Spin Coupling Constant: Overview

1.4K
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...
1.4K
Atomic Nuclei: Nuclear Spin State Population Distribution01:14

Atomic Nuclei: Nuclear Spin State Population Distribution

2.3K
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
2.3K
Spin–Spin Coupling: One-Bond Coupling01:17

Spin–Spin Coupling: One-Bond Coupling

1.4K
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,...
1.4K
Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)01:20

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)

1.6K
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...
1.6K
Valence Bond Theory02:42

Valence Bond Theory

11.2K
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...
11.2K

您也可能阅读

相关文章

通过共同作者、期刊和引用图与本文相关的文章。

排序
Same author

Adaptive Sampling of Singularities and Long Tails for Monte Carlo Integration of Electron Correlation.

The journal of physical chemistry letters·2026
Same author

Multi-Objective Optimization of Approximate Functionals via Implicit Interdependency Modeling.

Journal of chemical theory and computation·2026
Same author

Dynamic Coordination Modulation Governs Enantioselectivity in Rhodium-Catalyzed Hydrogenation with Mono- and Bidentate Phosphine Ligands.

The journal of physical chemistry. A·2025
Same author

Unveiling the Delicate Balance of Polarity and Strain Effect in Determining the Site-Selective Intramolecular Hydrogen Atom Transfers.

The journal of physical chemistry. A·2025
Same author

From Li<sub>2</sub>CO<sub>3</sub> to Li<sub>2</sub>C<sub>2</sub>O<sub>4</sub>: Understanding Discharge Product Decomposition in Li-CO<sub>2</sub> Batteries.

Inorganic chemistry·2025
Same author

From Single Atoms to Clusters: Unraveling the Structural Evolution of Pt/CeO<sub>2</sub> for Enhanced CO Oxidation.

The journal of physical chemistry letters·2025

相关实验视频

Updated: Jan 14, 2026

Spin Saturation Transfer Difference NMR SSTD NMR: A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes
11:44

Spin Saturation Transfer Difference NMR SSTD NMR: A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes

Published on: November 12, 2016

18.6K

一个基准数据库,用于单个和多重参考系统中使用 ΔDFT 和超越 ΔDFT 的 Spin-Flip Gap 计算.

Xiang Li1, Wenna Ai1, Neil Qiang Su1

  • 1Center for Theoretical and Computational Chemistry, Frontiers Science Center for New Organic Matter, State Key Laboratory of Advanced Chemical Power Sources, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Department of Chemistry, Nankai University, Tianjin 300071, China.

Journal of chemical theory and computation
|October 27, 2025
PubMed
概括
此摘要是机器生成的。

这项研究引入了一个用于分子中自旋翻转间隙 (SFG) 的基准数据库. 优化密度函数理论 (DFT) 和层次相关轨道函数理论 (HCOFT) 显示了准确的SFG预测的前景.

更多相关视频

All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
11:33

All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics

Published on: January 19, 2018

10.2K
Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
12:11

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry

Published on: April 8, 2020

8.7K

相关实验视频

Last Updated: Jan 14, 2026

Spin Saturation Transfer Difference NMR SSTD NMR: A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes
11:44

Spin Saturation Transfer Difference NMR SSTD NMR: A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes

Published on: November 12, 2016

18.6K
All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
11:33

All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics

Published on: January 19, 2018

10.2K
Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
12:11

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry

Published on: April 8, 2020

8.7K

科学领域:

  • 计算化学计算化学
  • 量子化学 是一个量子化学.
  • 理论化学 理论化学

背景情况:

  • 在分子系统中计算旋转翻转间隙 (SFG) 是很困难的,因为基准数据有限,开放单元状态的复杂性质.
  • 现有的方法经常在这些具有挑战性的系统的准确性和可扩展性方面扎.

研究的目的:

  • 为SFG建立一个全面的基准数据库,帮助开发和评估理论方法.
  • 为了评估各种密度函数理论 (DFT) 函数的性能和一种新的方法,层次相关轨道函数理论 (HCOFT),用于SFG计算.

主要方法:

  • 构建一个由419个数据点组成的SFG基准数据库,分为单参考 (SFG-SR) 和多参考 (SFG-MR) 的子集.
  • 评估32个DFT函数,使用DFT方法对SFG-SR子集进行评估.
  • 对SFG-MR子集的HCOFT变体,特别是1-HCOFT的评估,重点是准确性和基数组依赖性.

主要成果:

  • 混合DFT函数显著优于SFG-SR的半本地函数,Hartree-Fock交换内容对于准确性和扩展性至关重要.
  • 优化的 ΔDFT 方法为 SFG 预测提供了 (SF-) TDDFT 的实用和准确的替代方案.
  • 1-HCOFT表现出极好的准确性和单个二极根的低基数依赖性,显示出对大型多引用系统的希望.

结论:

  • 开发的基准数据库为推进SFG计算理论方法提供了可靠的基础.
  • 优化的DFT函数和1-HCOFT提供了可扩展和准确的策略,用于模拟各种分子系统中的自旋状态.
  • 这项工作弥合了基准数据和复杂电子结构的新兴理论方法之间的差距.