Related Experiment Video
Updated: Jul 3, 2026
09:57
Ultrafast Time-resolved Near-IR Stimulated Raman Measurements of Functional π-conjugate Systems
Published on: February 10, 2020
Investigating isomerization reactions in solid state by using simultaneous high overtone pumping and Raman detection.
Adriana Olbert-Majkut1, Jussi Ahokas, Jan Lundell
1Faculty of Chemistry,Wroclaw University, F. Joliot-Curie 14, Poland.
The Journal of Chemical Physics
|August 7, 2008
Summary
Direct laser excitation of trans-formic acid in solid argon efficiently induces isomerization to cis-formic acid. This Raman spectroscopy method enables ground electronic state chemical reaction studies in solids.
Area of Science:
- * Physical Chemistry
- * Molecular Spectroscopy
- * Solid-State Chemistry
Background:
- * Trans-formic acid is a fundamental molecule with a well-defined structure.
- * Studying molecular isomerization in solid matrices provides insights into reaction mechanisms under constrained conditions.
- * Direct vibrational excitation offers a pathway to induce chemical transformations in the ground electronic state.
Purpose of the Study:
- * To investigate the direct photoisomerization of trans-formic acid to its cis-form using vibrational excitation.
- * To develop and validate a Raman spectroscopy technique for monitoring solid-state chemical reactions.
- * To assess the efficiency of isomerization induced by a focused laser beam.
Main Methods:
- * Isomerization of trans-formic acid in a solid argon matrix via direct excitation of the nu(OH) vibration (6<--0 transition).
- * Utilization of a strongly focused laser beam for simultaneous pumping and Raman excitation.
- * Detection of reactants and products using Raman spectroscopy in a backscattering geometry.
Main Results:
- * Successful induction of cis-formic acid formation from trans-formic acid in a solid argon matrix.
- * Achieved relatively high isomerization rates despite the low absorption cross section.
- * Demonstrated simultaneous pumping and Raman excitation using a single laser source with overlapping excitation and probed volumes.
Conclusions:
- * Direct vibrational excitation is an effective method for inducing isomerization in solid-state molecules.
- * The developed Raman spectroscopy setup is suitable for studying ground electronic state chemical reactions in solid matrices.
- * This technique holds significant potential for future solid-state chemical reaction investigations.
Related Concept Videos
01:26Raman Spectroscopy Instrumentation: Overview
A conventional Raman spectrophotometer includes a laser source, a sample holding system, a wavelength selector, and a detector.
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
01:20Raman Spectroscopy: Overview
The underlying principle of Raman spectroscopy is based on the interaction between light and matter, specifically molecules' inelastic scattering of photons. When a monochromatic beam of light, typically from a laser source, interacts with a sample, most scattered light has the same frequency as the incident light. This is known as Rayleigh scattering.
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and the...
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and the...
01:12Double 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...
Spin decoupling is usually achieved by...
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
01:24IR Spectroscopy: Molecular Vibration Overview
When Infrared (IR) radiation passes through a covalently bonded molecule, the bonds transition from lower to higher vibrational levels. The fundamental vibrational motions that result in infrared absorption can be classified as stretching or bending vibrations.
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
01:08IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
Identical bonds within a polyatomic group can stretch symmetrically (in-phase) or asymmetrically (out-of-phase). Similar to hydrogen bonding, these vibrations also influence the shape of the IR peak. Generally, asymmetric stretching frequencies are higher than symmetric stretching frequencies. For example, primary amines exhibit two distinct IR peaks between 3300–3500 cm−1 corresponding to the symmetric and asymmetric N-H stretching, while secondary amines exhibit a single stretching vibration...