The mean field model with P-2 theta(2) coupling for the smectic A-smectic C* phase transition in liquid crystals

1998-01-01
Salihoglu, S
Yurtseven, Hasan Hamit
Giz, A
Kayisoglu, D
Konu, A
Using mean field theory with a P(2)theta (2) coupling term in the free energy expansion, we calculate the polarization as a function of temperature for the smectic A-smectic C* phase transition in a liquid crystalline material. Our calculated polarization values are in good agreement with the experimental data.
PHASE TRANSITIONS

Suggestions

A phase diagram near the NAC* point in liquid crystals
Salihoglu, S; Tublek, A; Yurtseven, Hasan Hamit (Informa UK Limited, 2000-01-01)
Wt study here a mean field model to obtain the phase diagram (concentration versus temperature) near the NAC* point in a binary mixture of liquid crystal. Wr have Fitted our phase line equations to the experimental data for the mixture of SCE9 + SCE10 liquid crystals. We deduce fi om our analysis that there should exist a tricritical point close to the NAC* point on the AC* phase line.
The lambda-phase transition in NH4Br
Yurtseven, Hasan Hamit; Sherman, WF (Informa UK Limited, 1996-01-01)
This study gives the predicted frequencies for the Raman modes of v(7)TA(56 cm(-1)), v(5)LO(177 cm(-1)) and v(2)(1684 cm(-1)) of NH4Br at various temperatures for zero pressure across the lambda-phase transition in this crystal system. We calculate the Raman frequencies by means of a constant mode Gruneisen parameter for each mode across the lambda-phase change region of NH4Br.
A mean-field model for the phase diagram of liquid crystals
Tublek, A; Yurtseven, Hasan Hamit; Salihoglu, S (Informa UK Limited, 1998-01-01)
In this study we have developed a mean-field model to obtain the phase diagram for a mixture of liquid crystals. Our mean-field model gives the phase diagram of the nematic, smectic A and smectic C phases near the NAC point. We have fitted our model to the experimentally observed data. From this fitting, we conclude that our mean-field model explains correctly the experimentally observed behavior of a mixed liquid crystalline system near the NAC point.
A phase diagram of ammonia close to the melting point
Salihoglu, S; Tari, O; Yurtseven, Hasan Hamit (Informa UK Limited, 2000-01-01)
We calculate here the phase line equations using the mean field theory for the liquid-solid I-solid II phases in the ammonia close to the melting point. Our calculated phase line equations have been fitted to the experimental data. Our calculated phase diagram agrees very well with the experimentally obtained P-T phase diagram from the literature.
The lambda-phase transitions in NH4Cl
Yurtseven, Hasan Hamit (Informa UK Limited, 1995-01-01)
We show here the correlations between the volume changes and the vibrational frequencies of the disorder-induced Raman modes of NH4Cl near the lambda-phase transitions of first order (P=0), tricritical (P similar or equal to 1.6 kbar) and second order (P similar or equal to 2.8 kbar). We obtain the values of the mode Gruneisen parameter for each phonon across the lambda-phase transitions and use them to predict the Raman frequencies for the phonon modes studied as functions of temperature in the lambda-phas...
Citation Formats
S. Salihoglu, H. H. Yurtseven, A. Giz, D. Kayisoglu, and A. Konu, “The mean field model with P-2 theta(2) coupling for the smectic A-smectic C* phase transition in liquid crystals,” PHASE TRANSITIONS, pp. 259–270, 1998, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/57856.