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: Two-Bond Coupling (Geminal Coupling)01:20

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

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

Spin–Spin Coupling: One-Bond Coupling

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,...
Spin–Spin Coupling Constant: Overview01:08

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

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

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 involved orbitals. The...
Double Resonance Techniques: Overview01:12

Double Resonance Techniques: Overview

Double resonance techniques in Nuclear Magnetic Resonance (NMR) spectroscopy involve the simultaneous application of two different frequencies or radiofrequency pulses to manipulate and observe two distinct nuclear spins. One important application of double resonance is spin decoupling, which selectively suppresses coupling with one type of nucleus while observing the NMR signal from another nucleus, simplifying the spectrum and enhancing resolution.
Spin decoupling is usually achieved by...
NMR Spectroscopy: Spin–Spin Coupling01:08

NMR Spectroscopy: Spin–Spin Coupling

The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved in...

You might also read

Related Articles

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

Sort by
Same author

Open- and Closed-Shell Roles of Sensitizer and Annihilator in Pseudo-Single Component Mixtures for Upconversion.

Journal of the American Chemical Society·2026
Same author

Efficient Nonadiabatic Molecular Dynamics with Machine Learning Hamiltonian Interpolation.

The journal of physical chemistry letters·2026
Same author

Anharmonic Effects Revealed by Temperature-Dependent Phonon Lifetimes and Thermal Conductivities in a π-Conjugated Molecular Crystal.

Journal of chemical theory and computation·2026
Same author

Electron transfer from singlet fission dimers: possibilities and limitations.

Chemical science·2026
Same author

Photochemical reduction of aryl chlorides, bromides, and iodides <i>via</i> ternary EDA complexes with guanidine bases.

Chemical science·2026
Same author

Limitations of quantum hardware for molecular energy estimation using VQE.

Physical chemistry chemical physics : PCCP·2026

Related Experiment Video

Updated: Jul 2, 2026

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
09:00

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser

Published on: June 28, 2018

The spin-flip extended single excitation configuration interaction method.

David Casanova1, Martin Head-Gordon

  • 1Department of Chemistry, University of California, Berkeley, California 94720, USA. davidcasanova@berkeley.edu

The Journal of Chemical Physics
|August 22, 2008
PubMed
Summary

A new computational method, spin-flip extended configuration interaction (SF-XCIS), accurately models complex molecular systems. This approach offers improved calculations for electronic states and chemical reactions in large molecules.

More Related Videos

Spin Saturation Transfer Difference NMR (SSTD NMR): A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes
11:44

Spin Saturation Transfer Difference NMR (SSTD NMR): A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes

Published on: November 12, 2016

Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
11:19

Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels

Published on: July 4, 2016

Related Experiment Videos

Last Updated: Jul 2, 2026

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser
09:00

Experimental Methods for Spin- and Angle-Resolved Photoemission Spectroscopy Combined with Polarization-Variable Laser

Published on: June 28, 2018

Spin Saturation Transfer Difference NMR (SSTD NMR): A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes
11:44

Spin Saturation Transfer Difference NMR (SSTD NMR): A New Tool to Obtain Kinetic Parameters of Chemical Exchange Processes

Published on: November 12, 2016

Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
11:19

Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels

Published on: July 4, 2016

Area of Science:

  • Quantum Chemistry
  • Computational Chemistry
  • Theoretical Chemistry

Background:

  • The spin-flip single excitation configuration interaction (SF-CIS) method is a valuable tool for studying electronic excited states.
  • However, SF-CIS has limitations in accurately describing certain electronic configurations, particularly in strongly correlated systems.

Purpose of the Study:

  • To introduce an extension of the SF-CIS method, termed spin-flip extended configuration interaction (SF-XCIS).
  • To develop a computationally efficient method applicable to large molecular systems and strongly correlated problems.

Main Methods:

  • The SF-XCIS method includes specific configurations derived from a high spin triplet reference determinant.
  • It employs a direct algorithm with a computational cost scaling quadratically with molecule size, similar to CIS.
  • The method ensures balanced treatment of half-occupied reference orbitals.

Main Results:

  • SF-XCIS yields spin-pure singlet, triplet, and quintet states.
  • The method demonstrates encouraging improvements over SF-CIS and the spin-complete CIS model.
  • Successful applications include bond dissociation in HF, ethylene's torsional potential, and excited states of polyenes.

Conclusions:

  • SF-XCIS provides a more accurate and versatile approach for electronic structure calculations.
  • The method's efficiency and accuracy make it suitable for studying complex chemical phenomena in large molecules.
  • This advancement facilitates deeper understanding of molecular properties and reaction mechanisms.