在合集群计算中,随机加速的扰动三倍校正.
Yann Damour1, Alejandro Gallo2, Anthony Scemama1
1Laboratoire de Chimie et Physique Quantiques (UMR 5626), Université de Toulouse, CNRS, UPS, Toulouse, France.
The Journal of chemical physics
|July 15, 2024
概括
一个新的半随机算法用于合集群计算提供了显著的计算节省. 这种方法在减少努力的情况下提供了准确的结果,使复杂的分子系统研究成为可能.
科学领域:
- 量子化学是一种量子化学.
- 计算物理学的计算物理.
- 理论化学是一种理论化学.
背景情况:
- 结合集群 (CC) 方法对于电子结构计算非常准确.
- 颠覆性三倍校正 (CC(2,3)) 对于高精度至关重要,但在计算上昂贵.
- 对于大型分子系统来说,CC的确定性计算 ((2,3) 是一个瓶.
研究的目的:
- 在合集群理论中开发一种新的,计算效率高的算法,用于扰乱的三倍校正.
- 为了平衡精度和计算成本,使用随机抽样.
- 为了使以前难以处理的分子系统能够进行准确的电子结构计算.
主要方法:
- 一个新的半随机算法的介绍. 半随机算法.
- 在结合集群框架内利用随机抽样技术.
- 结合确定性和随机元素进行计算.
主要成果:
- 该算法允许在任何时候终止计算,从而产生不偏见的估计.
- 随着准确计算的接近,统计误差会减少.
- 实现了0.5毫哈特的精度,仅占全方位方法计算成本的10%.
- 与传统的决定性方法相比,证明了大量的计算节省.
结论:
- 开发的半随机算法为扰乱的三倍校正提供了显著的计算成本降低.
- 该方法为准确和高效的电子结构计算提供了一条途径.
- 能够研究以前被计算资源所限制的复杂分子系统.
相关概念视频
Spin–Spin Coupling Constant: Overview
905
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...
905
Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
994
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...
994
Fermi Level Dynamics
235
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...
235
Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
1.1K
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
1.1K
Double Resonance Techniques: Overview
197
Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
Spin decoupling is usually achieved by...
197
Hybridization of Atomic Orbitals II
32.1K
sp3d and sp3d 2 Hybridization
32.1K


