Related Experiment Video
Updated: Mar 15, 2026
07:44
Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems
Published on: April 28, 2016
15.7K
Can the Resonance Raman Optical Activity Spectrum Display Sign Alternation?
Luciano N Vidal1, Tommaso Giovannini2, Chiara Cappelli2
1Universidade Tecnológica Federal do Paraná , Rua Deputado Heitor de Alencar Furtado, 4900, 81280-340, Curitiba, Brazil.
The Journal of Physical Chemistry Letters
|August 27, 2016
Summary
This study reveals sign alternation and intensity enhancement in resonance Raman optical activity (RROA) spectra by employing a quantum mechanical approach. This finding advances the analysis of chiral biological molecules using RROA.
Area of Science:
- Spectroscopy
- Quantum Chemistry
- Biophysical Chemistry
Background:
- Resonance Raman optical activity (RROA) spectra are typically assumed to have a monosignate character.
- This assumption is based on simplified theoretical models considering single electronic states and the Franck-Condon mechanism.
Purpose of the Study:
- To investigate the full quantum mechanical definition of RROA.
- To explore the impact of excited state interference and Herzberg-Teller effects on RROA spectra.
- To challenge the conventional understanding of RROA spectral characteristics.
Main Methods:
- Development and application of a fully quantum mechanical (QM) methodology.
- Inclusion of all relevant terms in the general RROA definition.
- Consideration of excited state interference and Herzberg-Teller effects.
Main Results:
- Demonstration of sign alternation in RROA spectra for the first time.
- Observation of intensity enhancement in RROA spectra.
- Validation of a more comprehensive theoretical framework for RROA.
Conclusions:
- The study provides a more complete theoretical understanding of RROA.
- The observed spectral features are crucial for analyzing chiral biological molecules.
- This work opens new avenues for RROA applications in molecular science.
Related Concept Videos
01:20Raman Spectroscopy: Overview
2.2K
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...
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and...
2.2K
01:26Raman Spectroscopy Instrumentation: Overview
1.6K
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...
1.6K
01:08IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
2.1K
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...
2.1K
01:24IR Spectroscopy: Molecular Vibration Overview
5.7K
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...
5.7K
02:24Properties of Enantiomers and Optical Activity
23.0K
It is essential to understand the difference between chiral and achiral interactions and the implications thereof in optical activity and their applications. Just as our feet, which are chiral, interact uniquely with chiral objects, such as a pair of shoes, but identically with achiral socks, enantiomers of a molecule exhibit different properties only when they interact with other chiral media. An example of a significant implication from this facet is the phenomenon known as optical activity,...
23.0K
02:16Resonance and Hybrid Structures
28.5K
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.
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.
28.5K