Related Experiment Video
Updated: Mar 22, 2026
07:52
A Novel Technique for Raman Analysis of Highly Radioactive Samples Using Any Standard Micro-Raman Spectrometer
Published on: April 12, 2017
13.5K
Structure of ZnCl2 Melt. Part I: Raman Spectroscopy Analysis Driven by Ab Initio Methods
Abduljabar Q Alsayoud1, Manga Venkateswara Rao1, Angharad N Edwards1
1Department of Materials Science and Engineering, University of Arizona , Tucson, Arizona 85721, United States.
The Journal of Physical Chemistry. B
|April 13, 2016
Summary
This study reveals molten zinc chloride (ZnCl2) contains many edge-sharing tetrahedra. These structural units significantly influence the properties of this glass-forming liquid.
Area of Science:
- Materials Science
- Computational Chemistry
- Physical Chemistry
Background:
- Understanding the structure of molten salts is crucial for predicting their properties.
- Molten zinc chloride (ZnCl2) is a representative tetrahedral glass-forming liquid with complex structural behavior.
Purpose of the Study:
- To elucidate the local structure and constituent units of molten ZnCl2.
- To revise the assignment of Raman bands based on detailed structural analysis.
- To investigate the impact of structural motifs on the properties of molten ZnCl2.
Main Methods:
- Ab initio molecular dynamics (AIMD) simulations at 600 K.
- Comparison of AIMD-derived structure factors and pair distribution functions with neutron diffraction (ND) data.
- Raman spectroscopy to identify structural units in liquid ZnCl2.
- First-principles calculations on crystalline ZnCl2 prototypes to assign Raman modes.
Main Results:
- AIMD simulations accurately reproduced experimental ND data for molten ZnCl2.
- Raman spectra analysis confirmed the presence of significant fractions of edge-sharing tetrahedra.
- First-principles calculations aided in assigning specific Raman modes to structural units.
- Excellent agreement between experimental and computational results validated the structural model.
Conclusions:
- The structure of molten ZnCl2 is characterized by a significant population of edge-sharing tetrahedra.
- These structural motifs are key to understanding the fragility of this glass-forming liquid.
- The revised assignment of Raman bands provides a more accurate interpretation of molten ZnCl2 spectroscopy.
Related Concept Videos
01:20Raman Spectroscopy: Overview
2.3K
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...
2.3K
01:26Raman Spectroscopy Instrumentation: Overview
1.7K
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...
1.7K
01:22Mass Spectrometry: Alkyl Halide Fragmentation
1.6K
Chlorine isotopes exist as 35Cl and 37Cl in a 3:1 ratio, while bromine isotopes exist as 79Br and 81Br in a 1:1 ratio. The mass spectrum of alkyl halides typically produces two distinct molecular ion peaks, the molecular ion peak, [M], and the molecular ion plus two, [M + 2] peak. The relative heights of these two peaks are proportional to the isotopic abundance ratios of the halide. For example, 2‐chloropropane and 1‐bromopropane display two peaks with relative peak heights in a 3:1 and...
1.6K
01:13¹H NMR: Complex Splitting
2.1K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
2.1K
01:08IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
2.2K
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...
2.2K
01:24Mass Spectrum: Interpretation
3.9K
An unknown compound can be established by identifying the molecular ion peak in the mass spectrum. The molecular ion peak is often weak or absent due to the predominance of fragmentation in high-energy electron beams. In such cases, a soft-energy electron beam can be used to scan the spectrum to enhance the intensity of the molecular ion peak. Additionally, chemical ionization, field ionization, and desorption ionization spectra are used to obtain a relatively intense molecular ion peak.To...
3.9K