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

Atomic Spectroscopy: Effects of Temperature01:27

Atomic Spectroscopy: Effects of Temperature

570
Atomization, converting samples into gas-phase atoms and ions, is essential for atomic spectroscopy. The flame temperature required for atomization affects the efficiency of the atomic spectroscopic methods by increasing the atomization efficiency and the relative population of the excited and ground states.
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature...
570
Thermochemical Equations02:55

Thermochemical Equations

32.8K
For a chemical reaction (the system) carried out at constant pressure – with the only work done caused by expansion or contraction – the enthalpy of reaction (also called the heat of reaction, ΔHrxn) is equal to the heat exchanged with the surroundings (qp).
32.8K
Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

2.6K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
2.6K
Thermal Sigmatropic Reactions: Overview01:16

Thermal Sigmatropic Reactions: Overview

2.2K
Sigmatropic rearrangements are a class of pericyclic reactions in which a σ bond migrates from one part of a π system to another. These are intramolecular rearrangements where the total number of σ and π bonds remain unchanged.
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in...
2.2K
Thermodynamics: Chemical Potential and Activity01:10

Thermodynamics: Chemical Potential and Activity

1.3K
The effective concentration of a species in a solution can be expressed precisely in terms of its activity. Activity considers the effect of electrolytes present in the vicinity of the species of interest and depends on the ionic strength of the solution. The activity of a species is expressed as the product of molar concentration and the activity coefficient of the species.
The thermodynamic equilibrium constant is more accurately defined in terms of activity rather than concentration.
1.3K
Thermodynamic Potentials01:26

Thermodynamic Potentials

1.1K
Thermodynamic potentials are state functions that are extremely useful in analyzing a thermodynamic system. They have dimensions of energy. The four important thermodynamic potentials are internal energy, enthalpy, Helmholtz free energy, and Gibbs free energy. These thermodynamic potentials can be expressed using two of the following variables: pressure, volume, temperature, and entropy. These two variables are expressed as the rate of change of the thermodynamic potential with respect to other...
1.1K

You might also read

Related Articles

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

Sort by
Same author

Master equation study of three-body recombination of nitrogen and oxygen in non-equilibrium hypersonic flows.

The Journal of chemical physics·2025
Same author

Efficient quasi-classical trajectory calculations by means of neural operator architectures.

Physical chemistry chemical physics : PCCP·2023
Same author

Rovibrational internal energy transfer and dissociation of high-temperature oxygen mixture.

The Journal of chemical physics·2023
Same author

Comprehensive Study of HCN: Potential Energy Surfaces, State-to-State Kinetics, and Master Equation Analysis.

The journal of physical chemistry. A·2022
Same author

Rovibrational-Specific QCT and Master Equation Study on N<sub>2</sub>(X<sup>1</sup>Σ<sub>g</sub><sup>+</sup>) + O(<sup>3</sup>P) and NO(X<sup>2</sup>Π) + N(<sup>4</sup>S) Systems in High-Energy Collisions.

The journal of physical chemistry. A·2022
Same author

Data-Inspired and Physics-Driven Model Reduction for Dissociation: Application to the O<sub>2</sub> + O System.

The journal of physical chemistry. A·2020

Related Experiment Video

Updated: Oct 25, 2025

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

8.4K

Carbon Clusters: Thermochemistry and Electronic Structure at High Temperatures.

Maitreyee P Sharma1, Richard L Jaffe2, Marco Panesi1

  • 1Center for Hypersonics and Entry Systems Studies (CHESS), University of Illinois, Urbana-Champaign, Urbana, Illinois 61801, United States.

The Journal of Physical Chemistry. A
|August 9, 2021
PubMed
Summary

Accurate thermochemistry for small carbon molecules (C3H, C4H) is crucial for understanding pyrolysis gases in heat shields. New calculations reveal excited states impact radiation absorption and thermodynamics, differing significantly from existing tables.

More Related Videos

Identification and Quantification of Decomposition Mechanisms in Lithium-Ion Batteries; Input to Heat Flow Simulation for Modeling Thermal Runaway
11:25

Identification and Quantification of Decomposition Mechanisms in Lithium-Ion Batteries; Input to Heat Flow Simulation for Modeling Thermal Runaway

Published on: March 7, 2022

4.8K
Combustion Chemistry of Fuels: Quantitative Speciation Data Obtained from an Atmospheric High-temperature Flow Reactor with Coupled Molecular-beam Mass Spectrometer
07:24

Combustion Chemistry of Fuels: Quantitative Speciation Data Obtained from an Atmospheric High-temperature Flow Reactor with Coupled Molecular-beam Mass Spectrometer

Published on: February 19, 2018

10.2K

Related Experiment Videos

Last Updated: Oct 25, 2025

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

8.4K
Identification and Quantification of Decomposition Mechanisms in Lithium-Ion Batteries; Input to Heat Flow Simulation for Modeling Thermal Runaway
11:25

Identification and Quantification of Decomposition Mechanisms in Lithium-Ion Batteries; Input to Heat Flow Simulation for Modeling Thermal Runaway

Published on: March 7, 2022

4.8K
Combustion Chemistry of Fuels: Quantitative Speciation Data Obtained from an Atmospheric High-temperature Flow Reactor with Coupled Molecular-beam Mass Spectrometer
07:24

Combustion Chemistry of Fuels: Quantitative Speciation Data Obtained from an Atmospheric High-temperature Flow Reactor with Coupled Molecular-beam Mass Spectrometer

Published on: February 19, 2018

10.2K

Area of Science:

  • Aerospace Engineering
  • Computational Chemistry
  • Chemical Physics

Background:

  • Pyrolysis gases, primarily small carbon clusters and hydrocarbons, are key components in the boundary layer of ablating heat shields.
  • Limited thermochemical data exists for crucial molecules like C3H and C4H, hindering accurate modeling.

Purpose of the Study:

  • To compute accurate thermochemistry and electronic structure data for small carbon clusters (up to four carbons) and hydrocarbons.
  • To investigate the role of electronically excited states in the thermochemistry and radiative properties of these species.
  • To assess the impact of these findings on hypersonic applications and compare with existing data.

Main Methods:

  • Employed the Weizmann-1 (W1) composite method for high-accuracy thermochemistry calculations.
  • Utilized the equations of motion coupled cluster singles doubles (EOM-CCSD) method to study electronically excited states.
  • Calculated electronic energies, heats of formation, harmonic frequencies, and rotational constants.

Main Results:

  • Determined thermochemistry data for C3H and C4H, including low-lying electronic states.
  • Identified C4 and C4H excited states as potential sources of radiation absorption in the boundary layer.
  • Found that neglecting excited states can lead to up to 12% error in specific heat capacity (Cp) values.
  • Observed an order of magnitude difference in mixture compositions compared to JANAF and Gurvich Tables.
  • The rhombic isomer of C4 significantly increases its equilibrium mole fraction by 28%.

Conclusions:

  • Accurate thermochemistry, including excited states, is essential for modeling pyrolysis gases in high-temperature regimes.
  • The computed data provides a more accurate basis for hypersonic applications, highlighting discrepancies with current standard tables.
  • The inclusion of typically neglected isomers like rhombic C4 is critical for accurate composition predictions.