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

Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)01:22

Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)

1.1K
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
1.1K
π Electron Effects on Chemical Shift: Overview01:27

π Electron Effects on Chemical Shift: Overview

1.1K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.1K
Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)01:20

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)

1.1K
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
1.1K
Spin–Spin Coupling Constant: Overview01:08

Spin–Spin Coupling Constant: Overview

1.0K
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...
1.0K
Spin–Spin Coupling: One-Bond Coupling01:17

Spin–Spin Coupling: One-Bond Coupling

1.0K
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
1.0K
¹H NMR: Long-Range Coupling01:27

¹H NMR: Long-Range Coupling

1.9K
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
1.9K

You might also read

Related Articles

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

Sort by
Same author

Atomistic Simulations of Fe(CO)<sub>5</sub> Fragmentation Dynamics on a Substrate.

The journal of physical chemistry. C, Nanomaterials and interfaces·2026
Same author

True <i>Schistosoma mansoni</i> eggs-cretome revealed by laser microdissection of infected mouse liver and intestine.

Frontiers in cellular and infection microbiology·2026
Same author

Design of electronically tunable fractional-order elements based on distributed MOS transistor structures.

Scientific reports·2026
Same author

Cluster Anions of Hydrated Polycyclic Aromatic Hydrocarbons: "Magic" Water Tetramer.

The journal of physical chemistry. A·2026
Same author

Functional characterization of secreted Schistosoma mansoni serpin SmSPI reveals factor XIIa inhibition as evidenced by biochemical and human plasma assays and supported by AI-assisted structural modeling.

International journal for parasitology·2026
Same author

Overset-Grid Method with Smooth Orbital Partitioning for Molecular Scattering Calculations.

Journal of chemical theory and computation·2025

Related Experiment Video

Updated: Sep 4, 2025

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
10:40

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy

Published on: June 28, 2016

7.6K

Vibronic Coupling through the Continuum in the e+CO_{2} System.

Jan Dvořák1, Miloš Ranković2, Karel Houfek1

  • 1Charles University, Faculty of Mathematics and Physics, Institute of Theoretical Physics, V Holešovičkách 2, 180 00 Prague 8, Czech Republic.

Physical Review Letters
|July 16, 2022
PubMed
Summary

High-resolution electron energy-loss spectra of carbon dioxide (CO2) reveal unexpected fine structures. A novel nonlocal model explains the complex vibronic dynamics and coupling of metastable states.

More Related Videos

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F&#8722;
06:53

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−

Published on: July 27, 2018

8.8K
Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
08:22

Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization

Published on: August 6, 2018

7.0K

Related Experiment Videos

Last Updated: Sep 4, 2025

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
10:40

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy

Published on: June 28, 2016

7.6K
Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F&#8722;
06:53

Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−

Published on: July 27, 2018

8.8K
Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
08:22

Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization

Published on: August 6, 2018

7.0K

Area of Science:

  • Chemical Physics
  • Molecular Spectroscopy
  • Quantum Dynamics

Background:

  • Studying the electronic and vibrational states of small molecules is crucial for understanding chemical reactions and molecular properties.
  • Carbon dioxide (CO2) exhibits complex excited-state dynamics, including Renner-Teller effects and pseudocontinuum formation, which are challenging to model.
  • Non-Born-Oppenheimer effects, where nuclear and electronic motions are strongly coupled, play a significant role in molecular excited states.

Purpose of the Study:

  • To investigate the high-resolution two-dimensional electron energy-loss spectra of carbon dioxide (CO2).
  • To elucidate the origin of counterintuitive fine structures observed in the spectra at energy losses corresponding to vibrational pseudocontinuum formation.
  • To develop a theoretical model explaining the non-Born-Oppenheimer vibronic dynamics of CO2.

Main Methods:

  • High-resolution two-dimensional electron energy-loss spectroscopy (2D-EELS) was employed to probe CO2 electronic states.
  • A four-dimensional nonlocal model was constructed, incorporating Renner-Teller effects and coupling to a virtual state.
  • The model focused on the vibronic dynamics involving shape resonances and their coupling to a continuum state.

Main Results:

  • The experiment revealed unexpected fine structures in the 2D-EELS spectra of CO2.
  • These structures were observed at energy losses where CO2 states form a vibrational pseudocontinuum.
  • The developed nonlocal model successfully elucidated the extremely non-Born-Oppenheimer dynamics and explained the observed spectral features.

Conclusions:

  • The study provides a detailed understanding of the vibronic coupling in carbon dioxide.
  • The observed fine structures are attributed to the complex interplay between electronic resonances and nuclear motion.
  • The developed model serves as a prototype for describing vibronic coupling of metastable states in continuum environments.