Related Experiment Video
Updated: May 26, 2026

Magnetic Tweezers for the Measurement of Twist and Torque
Published on: May 19, 2014
Coherent control of molecular torsion
Shane M Parker1, Mark A Ratner, Tamar Seideman
1Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
Abstract:
We propose a coherent, strong-field approach to control the torsional modes of biphenyl derivatives, and develop a numerical scheme to simulate the torsional dynamics. By choice of the field parameters, the method can be applied either to drive the torsion angle to an arbitrary configuration or to induce free internal rotation. Transient absorption spectroscopy is suggested as a probe of torsional control and the usefulness of this approach is numerically explored. Several consequences of our ability to manipulate molecular torsional motions are considered. These include a method for the inversion of molecular chirality and an ultrafast chiral switch.
Related Concept Videos
Conformations of Cyclohexane
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal tetrahedral value,...
MO Theory and Covalent Bonding
Cooperative Allosteric Transitions
Cooperative Allosteric Transitions
Cooperative Allosteric Transitions
Bending and Torsional Moments
The reaction developed in a structural element when subjected to an external force causes the element to bend. When a structural element bends upwards, it creates compressive normal forces on the top and tensile normal forces on the bottom, resulting in a couple that determines the bending...

