scholarly journals Application of the Pippard Relations to Cyclohexane near the Melting Point

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Hamit Yurtseven
Keyword(s):  
Experimental Data ◽  
Melting Point ◽  
Organic Compound ◽  
Critical Exponent ◽  
Power Law ◽  
Thermal Expansivity ◽  
Second Order ◽  
Order Transition ◽  
Thermodynamic Quantities ◽  
Second Order Transition

The Pippard relations are verified near the melting point for cyclohexane. The experimental data for the thermal expansivity is analyzed according to a power-law formula using the critical exponent and the thermodynamic quantities are calculated close to the melting point for this molecular organic compound. This applies to those compounds showing a second order transition prior to melting.

Critical Behaviour of the Heat Capacity Near the α-β Phase Transition in Quartz

2013 ◽  
Vol 32 (2) ◽  
pp. 189-194 ◽  
Author(s):  
H. Yurtseven ◽  
M. Desticioğlu
Keyword(s):  
Phase Transition ◽  
Heat Capacity ◽  
Critical Exponent ◽  
Power Law ◽  
Theoretical Models ◽  
Order Transition ◽  
Critical Behaviour ◽  
Experimental Heat ◽  
Β Phase ◽  
Second Order Transition

AbstractThe α-β transition (TQ = 578°C) is studied in quartz by analyzing the experimental heat capacity Cp data taken from the literature, using a power-law formula. Values of the critical exponent α for Cp are extracted below and above TQ, which describe the α-β transition as a second order transition in quartz. The α values obtained here are compared with the predictions of the theoretical models.

NMR · NQR and DTA · DSC Studies of Phase Transitions in Pyridinium Tetrachloropalladate(II) and Pyridinium Tetrachloroplatinate(II)

1998 ◽  
Vol 53 (6-7) ◽  
pp. 419-426 ◽  
Author(s):  
Tetsuo Asaji ◽  
Keizo Horiuchi ◽  
Takehiko Chiba ◽  
Takashige Shimizu ◽  
Ryuichi Ikeda
Keyword(s):  
Phase Transitions ◽  
Low Temperatures ◽  
Structural Phase ◽  
Orientational Order ◽  
Second Order ◽  
Order Transition ◽  
Spin Lattice Relaxation ◽  
Potential Wells ◽  
H Nmr ◽  
Second Order Transition

Abstract From the measurements of DTA • DSC and the temperature dependences of 35Cl NQR frequencies, phase transitions were detected at 150 K, 168 K, and 172 K for (pyH)2 [PtCl4], and at 241 K for (PyH)2 [PdCl4]. In order to elucidate the motional state of the constituent ions in the crystals in connection with the structural phase transitions, the 35Cl NQR and 1H NMR spin-lattice relaxation times and the second moment of the 1H NMR line were measured as functions of temperature. For both compounds, the potential wells for the cationic reorientation are suggested to be highly nonequivalent at low temperatures. Above 168 K, the pyridinium ions in (pyH)2[PtCl4] are expected to reorient between almost equivalent potential wells. As for (pyH)2[PdCl4], it is expected that the orientational order of the cation still remains even above the second order transition at 241 K. A change of the potential curve from two-unequal to three-unequal wells is proposed as a possible mechanism of the second order transition. The activation energies for the cationic motion in the respective model potential are derived for both compounds at high and low temperatures.

CRITICAL BEHAVIOR OF THE SPECIFIC HEAT IN THE VICINITY OF THE TRANSITION TEMPERATURE FOR S-TRIAZINE

2009 ◽  
Vol 23 (09) ◽  
pp. 2253-2259 ◽  
Author(s):  
M. KURT ◽  
H. YURTSEVEN
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Transition Temperature ◽  
Critical Exponent ◽  
Specific Heat ◽  
Power Law ◽  
Order Phase Transition ◽  
Critical Behavior ◽  
First Order ◽  
Second Order Phase Transition

The critical behavior of the specific heat is studied in s-triazine ( C 3 N 3 H 3). Using the experimental data for the CP, the temperature dependence of the specific heat is analyzed according to a power-law formula and the values of the critical exponent for CP are extracted in the vicinity of the transition temperature (TC=198.07 K ). It is indicated that s-triazine undergoes a weakly first order (quasi-continuous) or second order phase transition.

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