非传统的错误取消解释了Hartree-Fock密度函数理论对屏障高度的成功
Bikash Kanungo1, Aaron D Kaplan2, Chandra Shahi3
1Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States.
The journal of physical chemistry letters
|January 3, 2024
概括
计算化学通常低估了反应能量障碍. 这项研究表明,使用Hartree-Fock密度与半角函数校正错误,改善屏障高度预测.
科学领域:
- 量子化学 是一个量子化学.
- 计算化学计算化学
- 化学动力学 化学动力学
背景情况:
- 半局密度函数近似 (DFAs) 低估了对反应速率至关重要的能量障碍.
- 在Hartree-Fock (HF) 密度上评估DFAs可以提高屏障高度,这是30年来已知的现象.
- 主流的解释认为,这种改进是由于HF的电子密度更准确.
研究的目的:
- 在使用HF密度与DFAs时,调查反应屏障高度的精度提升的根本原因.
- 用精确的合集群 (CC) 密度来进行基准Kohn-Sham反转,用于H2 + F反应.
- 在这种情况下,阐明密度驱动和功能驱动错误之间的相互作用.
主要方法:
- 使用精确的合集群 (CC) 电子密度进行基准Kohn-Sham反转.
- 对H2 + F反应的过渡状态的分析.
- 从电子密度和交换相关函数近似结果中产生的错误的比较.
主要成果:
- 发现了密度驱动和功能驱动错误之间的强烈和可理解的取消.
- 发现来自密度近似的正误差和来自函数的大的负误差 (由于拉伸的根键) 取消.
- 这种取消解释了在高频密度上评估的DFA的提高准确性.
结论:
- 精度的提高不仅仅是由于HF密度更准确.
- 一个重要的错误取消机制解释了HF-DFA的成功.
- 这些发现与之前对76个障碍高度和非局部DFA代理的研究一致.
相关概念视频
Van der Waals Equation
4.1K
The ideal gas law is an approximation that works well at high temperatures and low pressures. The van der Waals equation of state (named after the Dutch physicist Johannes van der Waals, 1837−1923) improves it by considering two factors.
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
First, the attractive forces between molecules, which are stronger at higher densities and reduce the pressure, are considered by adding to the pressure a term equal to the square of the molar density multiplied by a positive coefficient a. Second, the volume...
4.1K
Electrostatic Boundary Conditions in Dielectrics
1.2K
When an electric field passes from one homogeneous medium to another, crossing the boundary between the two mediums imparts a discontinuity in the electric field. This results in electrostatic boundary conditions that depend on the type of mediums the field propagates through.
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's...
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's...
1.2K
Hybridization of Atomic Orbitals II
32.3K
sp3d and sp3d 2 Hybridization
32.3K
Hybridization of Atomic Orbitals I
47.1K
The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
47.1K
Fermi Level Dynamics
252
The vacuum level denotes the energy threshold required for an electron to escape from a material surface. It is usually positioned above the conduction band of a semiconductor and acts as a benchmark for comparing electron energies within various materials.
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...
252
Valence Bond Theory and Hybridized Orbitals
19.4K
According to valence bond theory, a covalent bond results when: (1) an orbital on one atom overlaps an orbital on a second atom, and (2) the single electrons in each orbital combine to form an electron pair. The strength of a covalent bond depends on the extent of overlap of the orbitals involved. Maximum overlap is possible when the orbitals overlap on a direct line between the two nuclei.
A σ bond (single bond in a Lewis structure) is a covalent bond in which the electron density is...
A σ bond (single bond in a Lewis structure) is a covalent bond in which the electron density is...
19.4K


