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

Double Resonance Techniques: Overview01:12

Double Resonance Techniques: Overview

203
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...
203
Resonance and Hybrid Structures02:16

Resonance and Hybrid Structures

16.9K
According to the theory of resonance, if two or more Lewis structures with the same arrangement of atoms can be written for a molecule, ion, or radical, the actual distribution of electrons is an average of that shown by the various Lewis structures.
Resonance Structures and Resonance Hybrids
The Lewis structure of a nitrite anion (NO2−) may actually be drawn in two different ways, distinguished by the locations of the N–O and N=O bonds.
16.9K
Deactivation Processes: Jablonski Diagram01:25

Deactivation Processes: Jablonski Diagram

650
Luminescence, the emission of light by a substance that has absorbed energy, is a process that involves the interaction of molecules with light. The energy-level diagram, or Jablonski diagram, is a graphical representation of these interactions, illustrating the various states and transitions a molecule can undergo. In a typical Jablonski diagram, the lowest horizontal line represents the ground-state energy of the molecule, which is usually a singlet state. This state represents the energies...
650
Molecular Spectroscopy: Absorption and Emission01:14

Molecular Spectroscopy: Absorption and Emission

2.3K
Molecules possess discrete energy levels called quantum states. Unlike atoms, which have simpler energy levels, molecules possess additional rotational and vibrational energy levels.  Each energy level is separated by an energy gap, with the gaps between adjacent electronic, vibrational, and rotational levels varying significantly. The three types of energy levels in a diatomic molecule are shown in Figure 1.
2.3K
Atomic Nuclei: Nuclear Relaxation Processes01:23

Atomic Nuclei: Nuclear Relaxation Processes

654
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis,  the precessing magnetic moments are randomly oriented around the z-axis.
654
¹H NMR: Interpreting Distorted and Overlapping Signals01:02

¹H NMR: Interpreting Distorted and Overlapping Signals

1.0K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.0K

You might also read

Related Articles

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

Sort by
Same author

Identifiability limits and deep-learning-assisted reconstruction of rotational density matrices for symmetric-top molecules.

The Journal of chemical physics·2026
Same author

Structural insights into spectral tuning and retinal exchange in cone visual pigments.

Science (New York, N.Y.)·2026
Same author

Lattice-Directed Spin-Vibronic Coherence-Mediated Ultrafast Intersystem Crossing in Crystalline Diplatinum Complex.

Journal of the American Chemical Society·2026
Same author

Enhancing IR-MALDESI MSI Spatial Resolution Through Beam Constriction With a Ring-Actuated Iris.

Rapid communications in mass spectrometry : RCM·2026
Same author

Rotor-stator repulsion and medium-induced dephasing enhance and equalise the quantum efficiency of a fluorinated photon-only rotary motor.

Nature communications·2026
Same author

Photochemistry of an Anti-Bredt Olefin through the Lens of Multistate Multireference Quantum Chemistry.

Journal of the American Chemical Society·2026

Related Experiment Video

Updated: Jul 1, 2025

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

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy

Published on: June 28, 2016

7.5K

Resonant multiphoton processes and excitation limits to structural dynamics.

William J C Francis1, Harmanjot Grewal1, Alexander A C Wainwright1

  • 1Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada and Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 3J1, Canada.

Structural Dynamics (Melville, N.Y.)
|March 4, 2024
PubMed
Summary

Researchers developed a theoretical framework to ensure photoexcitation conditions are biologically relevant. This framework helps avoid systematic errors in studying light-activated proteins by defining limits for one-photon excitation, crucial for understanding biological processes.

More Related Videos

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

6.9K
Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
10:35

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

Published on: May 29, 2018

8.7K

Related Experiment Videos

Last Updated: Jul 1, 2025

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

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy

Published on: June 28, 2016

7.5K
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

6.9K
Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
10:35

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals

Published on: May 29, 2018

8.7K

Area of Science:

  • Structural biology
  • Biophysics
  • Photochemistry

Background:

  • Studying light-activated biological processes requires ensuring experimental conditions mimic natural photoexcitation.
  • Current optical methods may use excessive excitation, leading to biologically irrelevant multiphoton absorption.
  • Systematic errors can arise if photoexcitation does not prepare a well-defined, biologically relevant initial state.

Purpose of the Study:

  • To develop a theoretical framework for evaluating and ensuring the biological relevance of photoexcitation conditions in experiments.
  • To define the excitation limits for studying structural dynamics within the one-photon excitation regime.
  • To identify conditions leading to resonant multiphoton absorption (RMPA).

Main Methods:

  • Development of a theoretical model to determine conditions for resonant multiphoton absorption (RMPA).
  • Application of the theoretical model to bacteriorhodopsin (bR) as a case study.
  • Analysis of excitation conditions relative to the linear saturation threshold.

Main Results:

  • The theoretical framework can identify excitation conditions that lead to RMPA.
  • RMPA in bacteriorhodopsin occurs below typical experimental excitation levels.
  • Experimental conditions exceeding the linear saturation threshold can lead to biologically irrelevant pathways.

Conclusions:

  • A theoretical framework is established to ensure photoexcitation relevance in biological studies.
  • Guidelines are provided to maintain one-photon excitation relevant to biological and chemical processes.
  • This work addresses systematic errors in photoactive biological process research.