Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Graphing the Wave Function01:13

Graphing the Wave Function

1.7K
Consider the wave equation for a sinusoidal wave moving in the positive x-direction. The wave equation is a function of both position and time. From the wave equation, two different graphs can be plotted.
1.7K
Fermi Level Dynamics01:12

Fermi Level Dynamics

217
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...
217
Equations of Wave Motion01:02

Equations of Wave Motion

5.6K
Mathematically, the motion of a wave can be studied using a wavefunction. Consider a string oscillating up and down in simple harmonic motion, having a period T. The wave on the string is sinusoidal and is translated in the positive x-direction as time progresses. Sine is a function of the angle θ, oscillating between +A and −A and repeating every 2π radians. To construct a wave model, the ratio of the angle θ and the position x is considered.
5.6K
Electromagnetic Wave Equation01:24

Electromagnetic Wave Equation

984
Maxwell's equations for electromagnetic fields are related to source charges, either static or moving. These fields act on a test charge, whose trajectory can thus be determined using suitable boundary conditions. The objective of electromagnetism is thus theoretically complete.
However, although electric and magnetic fields were first introduced as mathematical constructs to simplify the description of mutual forces between charges, a natural question emerges from Maxwell's equations:...
984
Interference and Superposition of Waves01:07

Interference and Superposition of Waves

4.8K
When two waves of the same nature occur in the same region simultaneously, they result in interference. Interference of waves implies that the net effect of the waves is the sum of the individual waves' effects. However, it does not imply that the individual waves affect the propagation of other waves.
Interference occurs in mechanical waves, such as sound waves, waves on a string, and surface water waves. Mechanical waves correspond to the physical displacement of particles. Hence,...
4.8K
Effective Value of a Periodic Waveform01:07

Effective Value of a Periodic Waveform

485
The concept of effective value, the root mean square (RMS) value, is crucial in understanding electrical circuits and power delivery. This idea emerges from the necessity to measure the effectiveness of a voltage or current source in supplying power to a resistive load.
The effective value of a periodic current represents the direct current (DC) that conveys the same average power to a resistor as the periodic current itself. This concept is crucial when assessing AC circuits. To determine the...
485

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Stochastic Difference-Dedicated Configuration Interaction for Magnetic Exchange in Large Active Spaces.

Journal of chemical theory and computation·2026
Same author

Spin-Adapted Restricted Open-Shell Hartree-Fock and Its Dynamic Correlation Extension.

Journal of chemical theory and computation·2026
Same author

Multireference perturbation theory reveals the intricate excited-state electronic structure of the 2-phenylpyridine ligand.

The Journal of chemical physics·2026
Same author

Modular construction of Jastrow factors for the transcorrelated method.

The Journal of chemical physics·2026
Same author

Stochastic-SplitGAS: A Quantum Monte Carlo Multi-Reference Perturbation Theory Based on the Imaginary-Time Evolution of Effective Hamiltonians.

Journal of chemical theory and computation·2025
Same author

A Genetic Algorithm Approach for Compact Wave Function Representations in Spin-Adapted Bases.

Journal of chemical theory and computation·2025
Same journal

Nuclear Gradients from Auxiliary-Field Quantum Monte Carlo and Their Applications in ML-Driven Geometry Optimization and Transition State Search.

Journal of chemical theory and computation·2026
Same journal

Correction to "Cluster-in-Molecule Local Correlation Method with an Accurate Distant Pair Correction for Large Systems".

Journal of chemical theory and computation·2026
Same journal

Machine-Learned Force Fields for Lattice Dynamics at Coupled-Cluster Level Accuracy.

Journal of chemical theory and computation·2026
Same journal

Systematic Molecularity-Dependent Entropy Errors in Continuum/RRHO Solution Thermochemistry: Origin and Correction.

Journal of chemical theory and computation·2026
Same journal

After 100 Years of Quantum Mechanics: Toward a Constructive Observation-Centered Perspective.

Journal of chemical theory and computation·2026
Same journal

Sample-Based Quantum Diagonalization Methods for Modeling the Photochemistry of Diazirine and Diazo Compounds.

Journal of chemical theory and computation·2026
See all related articles

Related Experiment Video

Updated: Jun 2, 2025

Generation and Coherent Control of Pulsed Quantum Frequency Combs
06:42

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Published on: June 8, 2018

8.9K

FCIQMC-CASPT2 with Imaginary-Time-Averaged Wave Functions.

Arta A Safari1, Robert J Anderson1, Ali Alavi1,2

  • 1Max-Planck-Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany.

Journal of Chemical Theory and Computation
|January 17, 2025
PubMed
Summary
This summary is machine-generated.

A new computational method enhances accuracy for large quantum systems. This approach resolves numerical issues, enabling more reliable predictions in complex molecular simulations.

More Related Videos

Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics
10:52

Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics

Published on: April 12, 2019

12.7K
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

8.1K

Related Experiment Videos

Last Updated: Jun 2, 2025

Generation and Coherent Control of Pulsed Quantum Frequency Combs
06:42

Generation and Coherent Control of Pulsed Quantum Frequency Combs

Published on: June 8, 2018

8.9K
Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics
10:52

Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics

Published on: April 12, 2019

12.7K
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

8.1K

Area of Science:

  • Quantum chemistry
  • Computational physics
  • Theoretical chemistry

Background:

  • Accurate electronic structure calculations are crucial for understanding molecular properties.
  • Large active spaces in quantum chemistry present significant computational challenges.
  • Full configuration interaction quantum Monte Carlo (FCIQMC) offers a path to treat large active spaces.

Purpose of the Study:

  • To develop a novel method for performing second-order perturbation theory (CASPT2) on large active spaces.
  • To address numerical instabilities and fermionic positivity violations in such calculations.
  • To apply and benchmark the new method on relevant chemical systems.

Main Methods:

  • Complete active space second-order perturbation theory (CASPT2).
  • Optimization of large active spaces using full configuration quantum Monte Carlo (FCIQMC).
  • Computation of density matrices from imaginary-time-averaged wave functions.

Main Results:

  • The developed method resolves fermionic positivity violations, ensuring numerical stability.
  • Successful application to complex systems like [NiFe]-hydrogenase, [Cu2O2]-oxidase, and Fe-porphyrin models.
  • Calculations involving up to 26 electrons in 27 orbitals were performed and benchmarked.

Conclusions:

  • The new CASPT2 protocol is robust and numerically stable for large active spaces.
  • This method provides a reliable approach for electronic structure calculations of challenging molecular systems.
  • The findings pave the way for more accurate theoretical studies in catalysis and bioinorganic chemistry.