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

NMR Spectroscopy: Spin–Spin Coupling

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...

¹H NMR: Long-Range Coupling

¹H NMR: Long-Range Coupling

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 π orbitals.

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...

Double Resonance Techniques: Overview

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...

Hybridization of Atomic Orbitals II

Hybridization of Atomic Orbitals II

sp3d and sp3d 2 Hybridization

Spin–Spin Coupling: One-Bond Coupling

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,...

You might also read

Related Articles

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

Sort by

Same author

The Newton-X platform for mixed quantum-classical dynamics.

Physical chemistry chemical physics : PCCP·2026

Same author

Flexible Framework for Surface Hopping: From Hybrid Schemes for Machine Learning to Benchmarkable Nonadiabatic Dynamics.

Journal of chemical theory and computation·2026

Same author

Preconfigured neuronal firing sequences in human brain organoids.

Nature neuroscience·2025

Same author

A Descriptor Is All You Need: Accurate Machine Learning of Nonadiabatic Coupling Vectors.

The journal of physical chemistry letters·2025

Same author

COLUMBUS─An Efficient and General Program Package for Ground and Excited State Computations Including Spin-Orbit Couplings and Dynamics.

The journal of physical chemistry. A·2025

Same author

Quantum Chemical and Trajectory Surface Hopping Molecular Dynamics Study of Iodine-Based BODIPY Photosensitizer.

Journal of computational chemistry·2025

Search research articles

Related Experiment Video

Updated: Jun 2, 2026

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry

Published on: April 8, 2020

Multireference state-specific Mukherjee's coupled cluster method with noniterative triexcitations using uncoupled

Kiran Bhaskaran-Nair¹, Ondrej Demel, Jan Smydke

¹J. Heyrovský Institute of Physical Chemistry, vvi, Academy of Sciences of the Czech Republic, Prague, Czech Republic.

The Journal of Chemical Physics

|April 26, 2011

Summary

This summary is machine-generated.

A new computational chemistry method, multireference Mukherjee's coupled cluster (MR MkCCSD(Tu)), simplifies calculations for molecular systems. This approach achieves high accuracy without iterative solutions for triple excitations, making complex quantum chemistry more accessible.

More Related Videos

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Published on: May 27, 2020

Related Experiment Videos

Last Updated: Jun 2, 2026

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry

Published on: April 8, 2020

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Published on: May 27, 2020

Area of Science:

Computational Chemistry
Quantum Chemistry
Theoretical Chemistry

Background:

Coupled cluster methods are essential for accurate electronic structure calculations.
Multireference coupled cluster (MRCC) methods are needed for systems with complex electronic structures.
Existing MRCC methods can be computationally demanding due to iterative solutions for high-order excitations.

Purpose of the Study:

To formulate a new, computationally efficient version of the multireference Mukherjee's coupled cluster method.
To introduce a method that avoids iterative solutions for triple excitation amplitudes.
To assess the accuracy and performance of the new method.

Main Methods:

Formulation of a new multireference Mukherjee's coupled cluster method with perturbative triexcitations.
Application of the uncoupled approximation to the triples equation.
Implementation of the method (MR MkCCSD(Tu)) in the ACES II program package.

Main Results:

The new MR MkCCSD(Tu) method provides results of comparable quality to existing iterative methods.
The method avoids the need for iterative solution of T(3) amplitudes, reducing computational cost.
Successful implementation and testing on the BeH(2) model and tetramethyleneethane molecule.

Conclusions:

The developed MR MkCCSD(Tu) method offers a computationally efficient alternative for accurate electronic structure calculations.
This approach simplifies the treatment of electron correlation in complex molecular systems.
The method shows promise for broader application in theoretical chemistry.