Related Experiment Video
Updated: Nov 24, 2025
05:39
Generating Strictly Controlled Stimuli for Figure Recognition Experiments
Published on: March 18, 2019
5.4K
The Shape of Full Configuration Interaction to Come
1School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom.
The Journal of Physical Chemistry Letters
|December 28, 2020
Summary
Full configuration interaction (FCI) theory is crucial for accurate quantum chemistry. While approximations have improved, enhancing near-exact electronic structure theory for larger systems remains a key challenge.
Area of Science:
- Quantum Chemistry
- Computational Chemistry
- Theoretical Chemistry
Background:
- Full configuration interaction (FCI) theory provides near-exact solutions to the electronic Schrödinger equation.
- Historically, FCI calculations were limited to small molecular systems due to high computational cost.
- Contemporary approximations aim to achieve FCI accuracy with reduced computational expense.
Purpose of the Study:
- To provide a perspective on the future of FCI theory, focusing on conceptual aspects.
- To compare key contemporary FCI approximations using a recent benchmark study.
- To discuss the indispensable applications and required traits of modern FCI approximations.
Main Methods:
- Revisiting the early history and conceptual development of FCI theory.
- Comparing contemporary FCI approximations on a benzene molecule benchmark.
- Reviewing the scope of applications and necessary characteristics (robustness, efficacy, reliability) of FCI approximations.
Main Results:
- The benzene molecule blind challenge served as a testbed for comparing FCI approximations.
- FCI theory remains indispensable for specific applications requiring high accuracy.
- Modern approximations must demonstrate robustness, efficacy, and reliability.
Conclusions:
- Significant progress has been made in FCI theory, especially in the last decade.
- Enhancing the applicability of near-exact electronic structure theory for larger and more complex systems is an ongoing challenge.
- Further advancements are needed to increase the general applicability of FCI for systems of general composition and size.
Related Concept Videos
02:11Conformations of Cyclohexane
14.5K
Cyclohexane does not exist in a planar form due to the high angle and torsional strain it would experience in the planar structure. Instead, it adopts non-planar chair and boat conformations.
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
14.5K
02:52VSEPR Theory and the Basic Shapes
79.9K
Overview of VSEPR Theory
79.9K
01:22Controller Configurations
229
Controller configurations are crucial in a car's cruise control system because they manage speed over time to maintain a consistent pace regardless of road conditions, thereby meeting design goals. In traditional control systems, fixed-configuration design involves predetermined controller placement. System performance modifications are known as compensation.
Control-system compensation involves various configurations, most commonly series or cascade compensation, in which the controller...
Control-system compensation involves various configurations, most commonly series or cascade compensation, in which the controller...
229
01:08Hückel's Rule Diagram of π MOs: Frost Circle
5.2K
The Frost circle or the inscribed polygon method is a graphical method for determining the relative energies of π molecular orbitals (MOs) for planar, fully conjugated, and monocyclic compounds. This method was first described by A. A. Frost and Boris Musulin in 1953.
A Frost circle is constructed by drawing a polygon whose number of edges is equal to the number of carbons of the given cyclic system, with one of the vertices pointing down. Then, a circle is drawn enclosing the polygon so that...
A Frost circle is constructed by drawing a polygon whose number of edges is equal to the number of carbons of the given cyclic system, with one of the vertices pointing down. Then, a circle is drawn enclosing the polygon so that...
5.2K
02:18Fischer Projections
15.6K
Learning to draw Fischer projections of molecules and understanding their relevance plays a crucial role in the visual depiction of organic molecules. A Fischer projection is a two-dimensional projection on a planar surface to simplify the three-dimensional wedge–dash representation of molecules. This is especially helpful in the case of molecules with multiple chiral centers that can be difficult to draw. Here, all the bonds of interest are represented as horizontal or vertical lines. While...
15.6K
02:02Chair Conformation of Cyclohexane
17.1K
The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
17.1K