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 Nuclei: Types of Nuclear Relaxation01:28

Atomic Nuclei: Types of Nuclear Relaxation

924
Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
924
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution00:52

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

1.3K
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
1.3K
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration01:16

IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration

2.8K
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to...
2.8K
¹H NMR of Labile Protons: Temporal Resolution01:10

¹H NMR of Labile Protons: Temporal Resolution

1.7K
Protons bonded to heteroatoms such as nitrogen and oxygen exhibit a range of chemical shift values. This is due to the varying degree of hydrogen bonding between the proton and the heteroatom in other molecules. The extent of hydrogen bonding affects the electron density around the proton, thereby giving different chemical shift values for the protons in the proton NMR spectrum.
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
1.7K
IR Spectroscopy: Molecular Vibration Overview01:24

IR Spectroscopy: Molecular Vibration Overview

4.5K
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
4.5K
Atomic Nuclei: Nuclear Relaxation Processes01:23

Atomic Nuclei: Nuclear Relaxation Processes

1.2K
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis,  the precessing magnetic moments are randomly oriented around the z-axis.
1.2K

You might also read

Related Articles

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

Sort by
Same author

Erratum: "State-to-state collision integrals and transport coefficients in oxygen mixtures" [J. Chem. Phys. 164, 084303 (2026)].

The Journal of chemical physics·2026
Same author

State-to-state collision integrals and transport coefficients in oxygen mixtures.

The Journal of chemical physics·2026
Same author

Correction to "State-Resolved Dissociation and Exchange Reactions in CO<sub>2</sub> Flows".

The journal of physical chemistry. A·2020
Same author

State-Resolved Dissociation and Exchange Reactions in CO<sub>2</sub> Flows.

The journal of physical chemistry. A·2019
Same author

Effect of Asymmetric Mode on CO<sub>2</sub> State-to-State Vibrational-Chemical Kinetics.

The journal of physical chemistry. A·2018
Same author

Mechanisms of Coupled Vibrational Relaxation and Dissociation in Carbon Dioxide.

The journal of physical chemistry. A·2018

Related Experiment Video

Updated: Jan 17, 2026

Author Spotlight: Exploring Intrinsically Disordered Protein Dynamics Through NMR Relaxation Experiments
09:25

Author Spotlight: Exploring Intrinsically Disordered Protein Dynamics Through NMR Relaxation Experiments

Published on: November 1, 2024

2.7K

Vibrationally state-resolved rotational relaxation time.

Y Yun1, E Kustova1

  • 1St. Petersburg University, 7-9 Universitetskaya Embankment, St. Petersburg 199034, Russia.

The Journal of Chemical Physics
|September 15, 2025
PubMed
Summary

This study introduces an improved computational model for rotational relaxation times, enhancing accuracy in high-temperature non-equilibrium flows. The new model overcomes limitations of rigid rotor assumptions, improving simulations for applications like atmospheric reentry.

More Related Videos

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
10:03

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

18.4K
Time-Resolved Fluorescence Anisotropy from Single Molecules for Characterizing Local Flexibility in Biomolecules
10:23

Time-Resolved Fluorescence Anisotropy from Single Molecules for Characterizing Local Flexibility in Biomolecules

Published on: April 25, 2025

928

Related Experiment Videos

Last Updated: Jan 17, 2026

Author Spotlight: Exploring Intrinsically Disordered Protein Dynamics Through NMR Relaxation Experiments
09:25

Author Spotlight: Exploring Intrinsically Disordered Protein Dynamics Through NMR Relaxation Experiments

Published on: November 1, 2024

2.7K
Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
10:03

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy

Published on: June 27, 2014

18.4K
Time-Resolved Fluorescence Anisotropy from Single Molecules for Characterizing Local Flexibility in Biomolecules
10:23

Time-Resolved Fluorescence Anisotropy from Single Molecules for Characterizing Local Flexibility in Biomolecules

Published on: April 25, 2025

928

Area of Science:

  • Fluid dynamics
  • Chemical physics
  • Computational modeling

Background:

  • Traditional Parker model fails in high-temperature non-equilibrium flows due to rigid rotor assumption.
  • Internal molecular structure significantly impacts energy transfer, posing a challenge for existing models.

Purpose of the Study:

  • Develop an advanced computational framework for rotational relaxation times.
  • Incorporate vibrational state-resolved calculations and rovibrational coupling for improved accuracy.

Main Methods:

  • Utilized variable soft sphere molecular model and statistical inelastic cross section theory.
  • Introduced an exponential correlation function for transition probabilities between rotational energy levels.
  • Established a complete state-to-state rotational relaxation time computational model.

Main Results:

  • Discovered a linear relationship between averaged rotational relaxation time and model parameter θ', simplifying parameter fitting.
  • Determined optimal θ' values for N2-N2, N2-N, O2-O2, and O2-O systems with <0.7% average relative error.
  • Provided validated computational guidelines for model application.

Conclusions:

  • The improved model offers accurate and efficient tools for transport coefficient calculations in hypersonic flow simulations.
  • Significant implications for engineering applications like atmospheric reentry and interplanetary exploration.
  • Overcomes limitations of simplified models for precise flow modeling.