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

Angular Momentum

Angular Momentum

Angular momentum characterizes an object's rotational motion and is defined as the moment of its linear momentum about a specified point O. When a particle moves along a curved path in the x-y plane, the scalar formulation calculates the magnitude of its angular momentum, utilizing the moment arm (d), representing the perpendicular distance from point O to the line of action of the linear momentum. Despite being scalar in formulation, angular momentum is inherently a vector quantity. Its...

Conservation of Angular Momentum: Application

Conservation of Angular Momentum: Application

A system's total angular momentum remains constant if the net external torque acting on the system is zero. Examples of such systems include a freely spinning bicycle tire that slows over time due to torque arising from friction, or the slowing of Earth's rotation over millions of years due to frictional forces exerted on tidal deformations. However in the absence of a net external torque, the angular momentum remains conserved. The conservation of angular momentum principle requires a change...

Conservation of Angular Momentum

Conservation of Angular Momentum

A system's total angular momentum remains constant if the net external torque acting on the system is zero. Considering a system that consists of n tiny particles, the angular momentum of any tiny particle may change, but the system's total angular momentum would remain constant. The principle of conservation of angular momentum only considers the net external torque acting on the system. While there are internal forces exerted by different particles within the system that also produce internal...

Angular Momentum: Single Particle

Angular Momentum: Single Particle

Angular momentum is directed perpendicular to the plane of the rotation, and its magnitude depends on the choice of the origin. The perpendicular vector joining the linear momentum vector of an object to the origin is called the “lever arm.” If the lever arm and linear momentum are collinear, then the magnitude of the angular momentum is zero. Therefore, in this case, the object rotates about the origin such that it lies on the rim of the circumference defined by the lever arm magnitude.
The...

Principle of Angular Impulse and Momentum

Principle of Angular Impulse and Momentum

The angular impulse and momentum principle provides insights into how forces applied at a distance from an object's rotational axis influence its angular velocity. It builds upon the crucial relationship between the moment of force and angular momentum. By integrating this equation, substituting the limits for the initial and final times, a comprehensive expression representing the angular impulse and momentum principle is derived.

Angular Momentum: Rigid Body

Angular Momentum: Rigid Body

The total angular momentum of a rigid body can be calculated using the summation of the angular momentum of all the tiny particles rotating in the same plane. Considering all the tiny particles rotating in the x-y plane, the direction of angular momentum of all such particles and that of the rigid body would be perpendicular to the plane of the rotation along the z-axis.
This calculation can get complicated when tiny particles within the rigid body are not rotating in the same plane but have...

You might also read

Related Articles

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

Sort by

Same author

Experimental realization of a π/2 vortex mode converter for electrons using a spherical aberration corrector.

Ultramicroscopy·2021

Same author

π/2 mode converters and vortex generators for electrons.

Ultramicroscopy·2019

Same author

Entanglement and decoherence in electron microscopy.

Ultramicroscopy·2018

Same author

EMCD with an electron vortex filter: Limitations and possibilities.

Ultramicroscopy·2017

Same author

Spin polarisation with electron Bessel beams.

Ultramicroscopy·2017

Same author

Spin polarisation with electron Bessel beams.

Ultramicroscopy·2016

Search research articles

Related Experiment Video

Updated: Jun 28, 2026

Study of Protein Dynamics via Neutron Spin Echo Spectroscopy

Study of Protein Dynamics via Neutron Spin Echo Spectroscopy

Published on: April 13, 2022

Exchange of angular momentum in EMCD experiments.

P Schattschneider¹

¹Institut für Festkörperphysik, Technische Universität Wien, A-1040 Wien, Austria. schattschneider@ifp.tuwien.ac.at

Ultramicroscopy

|October 28, 2008

Summary

Energy loss magnetic chiral dichroism (EMCD) experiments reveal that electron angular momentum conservation is complex. The chiral interaction transfers angular momentum to the probe electron, with the crystal lattice also contributing to the final photoelectron angular momentum.

More Related Videos

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

Published on: October 9, 2012

Neutron Spin Echo Spectroscopy as a Unique Probe for Lipid Membrane Dynamics and Membrane-Protein Interactions

Neutron Spin Echo Spectroscopy as a Unique Probe for Lipid Membrane Dynamics and Membrane-Protein Interactions

Published on: May 27, 2021

Related Experiment Videos

Last Updated: Jun 28, 2026

Study of Protein Dynamics via Neutron Spin Echo Spectroscopy

Study of Protein Dynamics via Neutron Spin Echo Spectroscopy

Published on: April 13, 2022

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

Published on: October 9, 2012

Neutron Spin Echo Spectroscopy as a Unique Probe for Lipid Membrane Dynamics and Membrane-Protein Interactions

Neutron Spin Echo Spectroscopy as a Unique Probe for Lipid Membrane Dynamics and Membrane-Protein Interactions

Published on: May 27, 2021

Area of Science:

Solid-state physics
Quantum mechanics
Materials science

Background:

Energy loss magnetic chiral dichroism (EMCD) probes chiral electronic transitions.
These transitions follow specific magnetic quantum number selection rules (Δm = ±1 or ΔL(z) = ±ħ).
Incident plane electron waves have zero angular momentum (L(z) = 0).

Purpose of the Study:

To resolve the apparent contradiction of angular momentum conservation in EMCD experiments.
To investigate the origin of angular momentum in photoelectrons generated during chiral electronic transitions.

Main Methods:

Analysis of electron scattering in EMCD experiments.
Theoretical examination of the probe electron's density matrix after chiral interaction.
Consideration of the role of the crystal lattice in angular momentum transfer.

Main Results:

Chiral interactions in EMCD induce a change in the probe electron's angular momentum (L(z) = ±ħ).
Angular momentum is not conserved as the probe electron exits the specimen due to lattice effects.
The crystal lattice breaks rotational symmetry, influencing angular momentum conservation.

Conclusions:

The angular momentum of photoelectrons in chiral transitions originates from both the probing electron and the crystal lattice.
A deeper understanding of electron-matter interactions and angular momentum dynamics in materials is achieved.
EMCD provides insights into the interplay between electronic structure and crystal symmetry.