Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

¹H NMR of Conformationally Flexible Molecules: Temporal Resolution

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...

Inductive Effects on Chemical Shift: Overview

Inductive Effects on Chemical Shift: Overview

The protons in unsubstituted alkanes are strongly shielded with chemical shifts below 1.8 ppm. Methine, methylene, and methyl protons appear at approximately 1.7, 1.2 and 0.7 ppm, while the proton signal from methane appears at 0.23 ppm. An electronegative substituent, such as chlorine, withdraws the electron density from the protons, increasing their chemical shift. Progressive substitution of the hydrogens in methane by chlorine shifts the proton signals increasingly downfield, to 3.05 ppm in...

Spin–Spin Coupling Constant: Overview

Spin–Spin Coupling Constant: Overview

In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...

Hybridization of Atomic Orbitals I

Hybridization of Atomic Orbitals I

The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...

¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR

¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR

The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.

π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds

π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds

In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as annulenes. In...

You might also read

Related Articles

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

Sort by

Same author

Interfacial Tuning of Anisotropic Gilbert Damping.

Physical review letters·2023

Same author

Inelastic neutron scattering study of tetramethylpyrazine in the complex with chloranilic acid.

Journal of physics. Condensed matter : an Institute of Physics journal·2020

Same author

Roux-en-Y-Bariatric Surgery Reduces Markers of Metabolic Syndrome in Morbidly Obese Patients.

Obesity surgery·2019

Same author

MSVAT-SPACE-STIR and SEMAC-STIR for Reduction of Metallic Artifacts in 3T Head and Neck MRI.

AJNR. American journal of neuroradiology·2018

Same author

Reduction of Premature Aging Markers After Gastric Bypass Surgery in Morbidly Obese Patients.

Obesity surgery·2018

Same author

Application of a Dedicated Surface Coil in Dental MRI Provides Superior Image Quality in Comparison with a Standard Coil.

Clinical neuroradiology·2016

Search research articles

Related Experiment Video

Updated: Jul 18, 2026

Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample

Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample

Published on: March 21, 2016

Methane clathrate: CH(4) quantum rotor state dependent rattling potential.

M Prager¹, W Press

¹Institut für Festkörperforschung, Forschungzzentrum Jülich, D-52425 Jülich, Germany. m.prager@fz-juelich.de

The Journal of Chemical Physics

|December 15, 2006

Summary

Methane molecules (CH4) in ice cages exhibit a rattling mode. This mode

Area of Science:

Solid-state physics
Materials science
Chemical physics

Background:

Methane hydrate exhibits unique properties due to guest-molecule encapsulation within ice cages.
The dynamic behavior of guest molecules influences the macroscopic properties of methane hydrate.

Purpose of the Study:

To investigate the influence of methane molecule rotational states on its rattling mode within methane hydrate cages.
To understand the relationship between guest molecule symmetry and cage interactions.

Main Methods:

Inelastic neutron scattering was used to probe the density of states in methane hydrate.
A two-state single-particle model was employed to analyze the rattling mode energies.

Main Results:

More Related Videos

Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex

Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex

Published on: July 27, 2022

Related Experiment Videos

Last Updated: Jul 18, 2026

Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample

Protocol for Measuring the Thermal Properties of a Supercooled Synthetic Sand-water-gas-methane Hydrate Sample

Published on: March 21, 2016

Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex

Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex

Published on: July 27, 2022

The dominant rattling mode of methane (CH4) in hydrate cages shifts from 6.7 meV at 4.5 K to 7.14 meV at 30 K.
This shift correlates with the conversion of methane molecules to a tunneling ground state, influenced by their less symmetric angular distribution in excited states.
The excited state allows better fitting within the cage, reducing rattling energy.

Conclusions:

The rotational state of methane molecules significantly impacts their rattling dynamics in hydrate cages.
A model incorporating distinct rattling energies for different methane states successfully explains the observed temperature-dependent behavior.