Spectroscopic modifications of Pippard relations for ammonium halides

Date

1997-11-01

Author

Yurtseven, Hasan Hamit

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

200
views

0
downloads

Spectroscopic modifications of the Pippard relations have been established for ammonium halides near their X-phase transitions. A linear relationship has been obtained between the specific heat and the frequency shifts using our observed Raman frequencies of the nu(5)TO(134 cm(-1)) and nu(5)LO(177 cm(-1)) lattice modes of NH4Br near its first-order phase transition (P = 0). Similar linear relationships have also been obtained using our observed Raman frequencies of the nu(5)TO(174 cm(-1)) lattice mode and the nu(2)(1708 cm(-1)) internal mode of NH4Cl near the tricritical (P similar or equal to 1.6 kbar) and the second-order (P similar or equal to 2.8 kbar) phase transitions in this crystal system. Our values of the slope (dP/dT)(lambda) deduced from the spectroscopic modifications of the Pippard relations are comparable with the literature value for the NH4Br crystal near its first-order phase transition. We also give in this study our (dP/dT)(lambda) values which are the first reported in the literature for the tricritical and the second-order phase transitions in NH4Cl. (C) 1997 Elsevier Science B.V.

Subject Keywords

Pippard relations, Raman frequency shifts, Ammonium halides

URI

https://hdl.handle.net/11511/57459

Journal

JOURNAL OF MOLECULAR STRUCTURE

DOI

https://doi.org/10.1016/s0022-2860(97)00175-0

Collections

Department of Physics, Article

Suggestions

OpenMETU
Core

Ultrasonic frequency shifts close to the first order and tricritical phase transitions in NH4Cl Yurtseven, Hasan Hamit; Bas, M (2001-12-01) This study examines our spectroscopic modifications of the Pippard relations using the ultrasonic frequencies of the q[110] and q[1 (1) over bar0] modes for the first order phase transition in NH4Cl. We also examine our relations using the ultrasonic frequencies of the q[110] mode for the tricritical phase transition in this crystal. From our plots of the specific heat C-p as a function of the frequency shifts (1/nu)(partial derivative nu/partial derivativeT)(p), we obtain that our spectroscopically modifie...
Spectroscopic modifications of Pippard relations: first-order and second-order phase transitions in NH4Cl Yurtseven, Hasan Hamit (2001-01-01) In this study we introduce the spectroscopic modifications of Pippard relations and apply them to the disorder-induced Raman modes of NH4Cl in the first-order (P = 0) and second-order (2.8 kbar) phase regions in this crystalline system. We obtain Linear variations of the specific heat C-p with out observed frequency shifts [(l/nu)(partial derivative nu/partial derivativeT)(p)] of those Raman modes studied for the first-order and second-order phase transitions in NH4Cl. This will be discussed in detail.
Spectroscopic modifications of the Pippard relations for NaNO2 in the sinusoidal antiferroelectric phase Tari, O; Yurtseven, Hasan Hamit (2002-06-01) We establish in this study a linear variation of the specific heat C-p with the frequency shifts (1/nu)(partial derivativenu/partial derivativeT) in the sinusoidal antiferroelectric phase of NaNO2, according to the first Pippard relation which we have modified spectroscopically. For this linear relationship we use the Brillouin frequencies of acoustic phonon modes for the q[010], q[001] and q[100] modes of NaNO2 in the sinusoidal antiferroelectric phase. We then calculate dT/dP values due to those modes stu...
SPECTROSCOPIC MODIFICATIONS OF PIPPARD RELATIONS AND THEIR APPLICATION TO NH4CL Yurtseven, Hasan Hamit (1994-07-01) The Pippard relations have been reformulated in terms of the spectroscopic parameters and applied to the NH4Cl system in the vicinity of its lambda-transition. We have effectively tested some of these relations in an earlier study where we have used, for the frequency shift, data for the nu5 lattice mode of NH4Cl. Here, using our observed frequency shifts for the internal mode, nu2 of NH4+, we have obtained a good fit to the Pippard relations for temperatures below T(lambda) for the NH4Cl system. We have th...
Frequency Modulated Raman Spectroscopy Greco, Silvio; Dal Zilio, Simone; Bek, Alpan; Lazzarino, Marco; Naumenko, Denys (2018-02-01) The coupling of plasmonic and mechanical properties at the nanoscale is of great potential for the development of next generation devices capable to detect weak forces, mass changes, minute displacements and temperature induced effects. Both the transduction of mechanical motion to the scattered light fields in term of polarization or intensity modulation and plasmon-driven mechanical oscillations have already been demonstrated. Quasi static tunable hot spots have recently been designed and applied to surfa...

Citation Formats

H. H. Yurtseven, “Spectroscopic modifications of Pippard relations for ammonium halides,” JOURNAL OF MOLECULAR STRUCTURE, pp. 143–150, 1997, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/57459.