Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Search research articles

Related Experiment Videos

Bandwidths studied as a function of temperature in ammonium halides near Tlambda.

¹Department of Physics, Middle East Technical University, 06531 Ankara, Turkey. phys@metu.edu.tr

Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy

|August 16, 2005

Summary

This study analyzes Raman bandwidths in ammonium halides near phase transitions using a soft mode-hard mode coupling model. Researchers determined a critical exponent value of beta=0.13 for the order parameter in the first-order phase region.

Related Concept Videos

You might also read

Related Articles

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

Sort by

Same author

Temperature dependence of the polarization and the dielectric constant near the paraelectric-ferroelectric transitions in BaTiO3.

Journal of molecular modeling·2013

Same author

Analysis of the Raman intensities near the phase transitions in ammonium halides.

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy·2008

Same author

Temperature dependence of the Raman bandwidths for the lattice and internal modes in ammonium halides close to the lambda-phase transitions.

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy·2008

Same author

Pippard relations applied to the lambda-phase transition in NH4Br.

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy·2008

Same author

A linear variation of the thermal expansivity with frequency shifts for the translational mode in ammonia solid II near the melting point.

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy·2007

Same author

Specific heat and frequency shifts for the translational modes in ammonia solid I close to phase transition.

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy·2006

Area of Science:

Solid-state physics
Materials science
Spectroscopy

Background:

Ammonium halides exhibit complex phase transitions.
Raman spectroscopy is crucial for understanding lattice dynamics.
Soft mode-hard mode coupling models explain phase transition behavior.

Purpose of the Study:

To analyze the temperature dependence of Raman bandwidths in ammonium halides.
To apply the soft mode-hard mode coupling model to ammonium chloride (NH4Cl) and ammonium bromide (NH4Br).
To determine critical exponent values near phase transitions.

Main Methods:

Raman spectroscopy was used to measure bandwidths of specific modes (nu5).
The soft mode-hard mode coupling model was employed for analysis.

Related Experiment Videos

Temperature dependence of bandwidths near phase transitions was investigated.

Main Results:

The temperature dependence of the nu5 Raman mode bandwidths for NH4Cl and NH4Br was analyzed.
The soft mode-hard mode coupling model was successfully applied.
A critical exponent value of beta=0.13 was obtained for the order parameter.

Conclusions:

The study provides insights into the phase transition mechanisms of ammonium halides.
The determined critical exponent (beta=0.13) characterizes the order parameter behavior.
The soft mode-hard mode coupling model effectively describes the observed phenomena.