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

Calculating the Equilibrium Constant02:46

Calculating the Equilibrium Constant

37.6K
The equilibrium constant for a reaction is calculated from the equilibrium concentrations (or pressures) of its reactants and products. If these concentrations are known, the calculation simply involves their substitution into the Kc expression.
For example, gaseous nitrogen dioxide forms dinitrogen tetroxide according to this equation:
37.6K
Calculating Standard Free Energy Changes02:49

Calculating Standard Free Energy Changes

24.7K
The free energy change for a reaction that occurs under the standard conditions of 1 bar pressure and at 298 K is called the standard free energy change. Since free energy is a state function, its value depends only on the conditions of the initial and final states of the system. A convenient and common approach to the calculation of free energy changes for physical and chemical reactions is by use of widely available compilations of standard state thermodynamic data. One method involves the...
24.7K
Calculating pH Changes in a Buffer Solution02:45

Calculating pH Changes in a Buffer Solution

57.7K
A buffer can prevent a sudden drop or increase in the pH of a solution after the addition of a strong acid or base up to its buffering capacity; however, such addition of a strong acid or base does result in the slight pH change of the solution. The small pH change can be calculated by determining the resulting change in the concentration of buffer components, i.e., a weak acid and its conjugate base or vice versa. The concentrations obtained using these stoichiometric calculations can be used...
57.7K
Numerical Calculations01:24

Numerical Calculations

1.2K
In engineering applications, the representation of the numerical value is critical. Presenting or reporting the answer is one of the essential parts of engineering practices. Numerical calculations are performed using handheld calculators or computers since numerically accurate answers are always preferred.
The solution to a problem is obtained using different methods. While manually solving algebraic symbols is one of the most common methods, the graphical method is often preferred. Computers...
1.2K
Net Torque Calculations01:19

Net Torque Calculations

11.3K
When a mechanic tries to remove a hex nut with a wrench, it is easier if the force is applied at the farthest end of the wrench handle. The lever arm is the distance from the pivot point (the hex nut in this case) to the person’s hand. If this distance is large, the torque is higher. Only the component of the force perpendicular to the lever arm contributes to the torque. Therefore, pushing the wrench perpendicular to the lever arm is more advantageous. If multiple people apply force to...
11.3K
Calculating Equilibrium Concentrations02:05

Calculating Equilibrium Concentrations

52.7K
Being able to calculate equilibrium concentrations is essential to many areas of science and technology—for example, in the formulation and dosing of pharmaceutical products. After a drug is ingested or injected, it is typically involved in several chemical equilibria that affect its ultimate concentration in the body system of interest. Knowledge of the quantitative aspects of these equilibria is required to compute a dosage amount that will solicit the desired therapeutic effect.
A more...
52.7K

You might also read

Related Articles

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

Sort by
Same author

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

Journal of chemical theory and computation·2026
Same author

Short-Range Machine-Learning Potentials for Aqueous Electrolyte Solutions.

Chemphyschem : a European journal of chemical physics and physical chemistry·2026
Same author

Neural Quantum States Based on Selected Configurations.

The journal of physical chemistry letters·2026
Same author

How to Use Quantum Computers for Biomolecular Free Energies.

Journal of chemical theory and computation·2026
Same author

Extensions to Extended Tight-Binding Methods for Transition-Metal Containing Systems.

Journal of computational chemistry·2026
Same author

Modal Backflow Neural Quantum States for Anharmonic Vibrational Calculations.

Journal of chemical theory and computation·2026

Related Experiment Video

Updated: Jan 23, 2026

Semi-automated Optical Heartbeat Analysis of Small Hearts
12:10

Semi-automated Optical Heartbeat Analysis of Small Hearts

Published on: September 16, 2009

12.8K

autoCAS: A Program for Fully Automated Multiconfigurational Calculations.

Christopher J Stein1, Markus Reiher1

  • 1ETH Zürich, Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland.

Journal of Computational Chemistry
|June 8, 2019
PubMed
Summary
This summary is machine-generated.

We developed autoCAS, a free software for automated multiconfigurational calculations. This tool simplifies complex quantum chemistry computations, making them accessible for broader research applications.

Keywords:
CASSCFab initio calculationsquantum chemical calculations

More Related Videos

Computer-based Multitaper Spectrogram Program for Electroencephalographic Data
04:13

Computer-based Multitaper Spectrogram Program for Electroencephalographic Data

Published on: November 13, 2019

12.8K
Automated Acoustic Dispensing for the Serial Dilution of Peptide Agonists in Potency Determination Assays
08:06

Automated Acoustic Dispensing for the Serial Dilution of Peptide Agonists in Potency Determination Assays

Published on: November 10, 2016

7.9K

Related Experiment Videos

Last Updated: Jan 23, 2026

Semi-automated Optical Heartbeat Analysis of Small Hearts
12:10

Semi-automated Optical Heartbeat Analysis of Small Hearts

Published on: September 16, 2009

12.8K
Computer-based Multitaper Spectrogram Program for Electroencephalographic Data
04:13

Computer-based Multitaper Spectrogram Program for Electroencephalographic Data

Published on: November 13, 2019

12.8K
Automated Acoustic Dispensing for the Serial Dilution of Peptide Agonists in Potency Determination Assays
08:06

Automated Acoustic Dispensing for the Serial Dilution of Peptide Agonists in Potency Determination Assays

Published on: November 10, 2016

7.9K

Area of Science:

  • Computational chemistry
  • Quantum chemistry
  • Electronic structure theory

Background:

  • Multiconfigurational calculations are essential for accurately describing complex chemical systems.
  • However, these calculations are often computationally demanding and require expert knowledge for setup.
  • Automated protocols are needed to streamline these processes.

Purpose of the Study:

  • To present autoCAS, a software implementation for fully automated multiconfigurational calculations.
  • To enable black-box multiconfigurational calculations comparable in ease of use to standard density-functional theory.
  • To introduce an extension for handling large molecular systems with extensive valence orbital spaces.

Main Methods:

  • Development of autoCAS software with a graphical user interface.
  • Integration of general electronic structure programs with a density-matrix renormalization group program.
  • Implementation of an automated active space selection protocol.
  • Extension of the selection algorithm for large valence orbital spaces.

Main Results:

  • autoCAS provides a user-friendly interface for automated multiconfigurational calculations.
  • The software requires minimal input, similar to Kohn-Sham density-functional theory calculations.
  • An enhanced selection algorithm successfully handles systems with several hundred valence orbitals.

Conclusions:

  • autoCAS makes advanced multiconfigurational calculations feasible and accessible.
  • The software significantly reduces the complexity and expertise required for such computations.
  • This tool facilitates broader application of accurate quantum chemical methods in research.