Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
Calculation of the Raman and IR frequencies as order parameters and the damping constant (FWHM) close to phase transitions in methylhydrazinium structures
Date
2019-4
Author
Kurt, M.
Yurtseven, Hasan Hamit
Kurt, A.
Metadata
Show full item record
Item Usage Stats
229
views
0
downloads
Cite This
Temperature dependences of the frequencies for the Raman modes of v (NH2), v(s) (CH3), v(1) (HCOO-), vs (CNN) and IR mode of rho (NH2) are calculated in particular, for MHyMn close to the phase transition temperature (T-C = 220 K) in the family of compounds CH3NH2NH2 M(HCOO)(3), MHyM with M = Mn, Mg, Fe and Zn. By assuming Raman and infrared frequency as an order parameter, this calculation is performed from the molecular field theory by using the experimental data from the literature. We also calculate the damping constant (FWHM) from the order parameter (Raman and IR frequency of those modes) by using the pseudospin (MHy(+) cations)-phonon coupled model (PS) and the energy-fluctuation model (EF) for methylhydrazinium metal formate frameworks. Expressions of the damping constant from both models are fitted to the observed FWHM data for the Raman and infrared modes studied for these metal formates. Our results show that the anomalous behaviour of the Raman and IR frequencies of those modes, except the v(S)(CH3) Raman mode which are associated with the phase transition can be described adequately by the molecular field theory in MHyM, as observed experimentally. Also, the damping constant calculated from the PS and EF models can explain the observed FWHM of those Raman and IR modes studied in methylhydrazinium metal formate frameworks.
Subject Keywords
Order parameter
,
Damping constant
,
Raman and IR modes
,
Phase transition
,
MHyMn
URI
https://hdl.handle.net/11511/28563
Journal
Journal of Molecular Structure
DOI
https://doi.org/10.1016/j.molstruc.2019.01.016
Collections
Department of Physics, Article
Suggestions
OpenMETU
Core
Calculation of the Raman frequency and the damping constant (linewidth) of the stretching modes for the metal-organic compound DMMg close to the paraelectric-ferroelectric transitions
Yurtseven, Hasan Hamit (2018-01-01)
We calculate the Raman frequencies of the two stretching modes of as a function of temperature close to the paraelectric-ferroelectric transition (Tc = 270K) in (CH3)(2)NH2Mg(HCOO)(3) referred as DMMg. By assuming that the Raman frequencies of those two modes which exhibit anomalous behaviour near Tc due to the ordering of the dimethlyammonium cations (DMA(+)) as observed experimentally, are associated with the spontaneous polarization (order parameter), their Raman frequencies and damping constants are pre...
Calculation of the Spontaneous Polarization and the Dielectric Constant as a Function of Temperature for KH2PO4
Yurtseven, Hasan Hamit (2012-01-01)
The temperature dependence of the spontaneous polarization P is calculated in the ferroelectric phase (T < T-C) of KH2PO4 (KDP) at atmospheric pressure (T-C = 122 K). Also, the dielectric constant e is calculated at various temperatures in the paraelectric phase (T > T-C) of KDP at atmospheric pressure. For this calculation of P and epsilon, by fitting the observed Raman frequencies of the soft mode, the microscopic parameters of the pure tunnelling model are obtained. In this model, the proton-lattice inte...
Calculation of the damping constant and the order parameter for the lattice mode in ferroelectric PbTiO3
Kiraci, A.; Yurtseven, Hasan Hamit (2013-07-25)
The temperature dependences of the damping constant and the order parameter are calculated for the lattice mode of E (1TO) in PbTiO3 using the experimental data by the pseudospin- phonon coupled model and the enrgy fluctuation model. Calculation of the damping constant of soft mode is performed in the temperature range of 400- 490 degrees C close to the ferroelectric- paraelectric transition (T-C= 493 degrees C) in PbTiO3. By relating the frequency to the order parameter, the temperature dependence of the R...
Calculation of the Brillouin frequencies close to phase transitions in NaNO2
Yurtseven, Hasan Hamit (2002-01-01)
We calculate here the Brillouin frequencies of the L-mode [010], [001] and [100] of NaNO2 for the phase transitions from the paraelectric phase to the sinusoidal anti-ferroelectric phase near the Neel temperature (T-N = 437.7 K) and to the ferroelectric phase near the critical temperature (T-c = 436.3 K) in this crystalline system. For calculating the frequencies, we use the thermal expansivity data for the phase regions considered, under the assumption that the mode Gruneisen parameter determined for each ...
Calculation of the Raman frequencies as a function of temperature in phase I of benzene
Tari, O.; Yurtseven, Hasan Hamit (2013-06-01)
This study gives our calculation of the Raman frequencies of the lattice modes A (A(1g)), B (A(g)B(2g)) and C (B1gB3g) as a function of temperature at constant pressures of 0, 1.4 and 3.05 GPa for the solid phase I of benzene. The Raman frequencies of those lattice modes are calculated using the volume data from the literature through the mode Gruneisen parameters for the solid phase I of this molecular crystal. It is shown here that the Raman frequencies of the lattice modes studied decrease with increasin...
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
M. Kurt, H. H. Yurtseven, and A. Kurt, “Calculation of the Raman and IR frequencies as order parameters and the damping constant (FWHM) close to phase transitions in methylhydrazinium structures,”
Journal of Molecular Structure
, pp. 488–492, 2019, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/28563.