scholarly journals THERMODYNAMIC QUANTITIES AT HIGH PRESSURES IN THE i AND θ PHASES OF SOLID NITROGEN DEDUCED BY RAMAN FREQUENCY SHIFTS FOR THE INTERNAL MODES IN LITERATURE

2013 ◽  
Vol 27 (09) ◽  
pp. 1350035 ◽  
Author(s):  
H. YURTSEVEN ◽  
S. SARITAŞ
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Specific Heat ◽  
Pressure Dependence ◽  
Isothermal Compressibility ◽  
High Pressures ◽  
Raman Frequency ◽  
Thermodynamic Quantities ◽  
Frequency Shifts ◽  
Solid Nitrogen

The pressure dependence of the Raman frequencies of the internal modes is analyzed (T = 300 K ) for the phases i and θ of solid nitrogen using the experimental data from the literature. Through the mode Grüneisen parameter, the isothermal compressibility κT, thermal expansion αp and the specific heat Cp–Cv are calculated as a function of pressure using the Raman data in these phases. We obtain that the αp varies linearly with the (1/υ)(∂υ/∂P)T and also that the Cp–Cv varies linearly with the αp for N 2. Our results show that by means of the analysis given here, the αp, κT and Cp–Cv can be predicted from the Raman frequency shifts for the i and θ phases of solid nitrogen.

scholarly journals Analysis of the Raman Frequency Shifts for the Lattice Modes and Vibrons Related to the Thermodynamic Quantities in the η Phase of Solid Nitrogen

2013 ◽  
Vol 32 (4) ◽  
pp. 383-389 ◽  
Author(s):  
Hamit Yurtseven ◽  
Özge Akay
Keyword(s):  
Thermal Expansion ◽  
Specific Heat ◽  
Isothermal Compressibility ◽  
Raman Frequency ◽  
Thermodynamic Quantities ◽  
Frequency Shifts ◽  
Solid Nitrogen ◽  
Lattice Modes

AbstractThe thermodynamic quantities of the isothermal compressibility, thermal expansion and the specific heat are calculated here as a function of pressure by using the observed Raman frequencies of the lattice modes and vibrons in the η phase of solid nitrogen. The Pippard relations and their spectroscopic modifications are constructed, and the slope dP/dT is deduced from the Raman frequency shifts in this phase of N2. It is shown that the thermodynamic quantities can be predicted from the Raman frequency shifts, in particular, in the η phase of solid nitrogen.

PIPPARD RELATIONS MODIFIED FOR THE RAMAN FREQUENCY SHIFTS CLOSE TO I–II PHASE TRANSITION IN S-TRIAZINE

2011 ◽  
Vol 25 (32) ◽  
pp. 4641-4653
Author(s):  
H. YURTSEVEN ◽  
M. KURT
Keyword(s):  
Phase Transition ◽  
Specific Heat ◽  
Pressure Dependence ◽  
Isothermal Compressibility ◽  
Raman Frequency ◽  
Experimental Measurements ◽  
Frequency Shifts ◽  
Raman Modes

The pressure dependence of the frequency shifts 1/ω(∂ω/∂T)P is calculated from the 1/ω(∂ω/∂P)T for the Raman modes I and IV according to the spectroscopic modifications of the Pippard relations. The observed Raman frequencies of those modes are used for this calculation close to the I–II phase transition in s-triazine. From the frequency shifts, the isothermal compressibility κT and the specific heat CP are also calculated as a function of pressure close to the I–II phase transition in s-triazine. Our calculated values of 1/ω(∂ω/∂T)P κT and CP can be compared with the experimental measurements at various pressures in the phases I and II of s-triazine.

Pressure Dependence of the Thermodynamic Quantities in Phase II of Solid Benzene

2013 ◽  
Vol 32 (5) ◽  
pp. 421-425 ◽  
Author(s):  
H. Yurtseven ◽  
E. Sevinc
Keyword(s):  
Phase Ii ◽  
Pressure Dependence ◽  
Isothermal Compressibility ◽  
Molecular Crystal ◽  
Pressure Range ◽  
High Pressures ◽  
Solid Phase ◽  
Experimental Measurements ◽  
Thermodynamic Quantities ◽  
Volume Data

AbstractThe thermodynamic quantities such as the thermal expansion (αp), isothermal compressibility (KT) and the specific heat (CP − CV), are predicted at various pressures up to 26 GPa (T = 540 K) in the solid phase II of benzene using volume data from the literature. The Pippard relations are examined using the pressure dependence of αp, KT and CP − CV and the value of the slope dP/dT is deduced for the solid phase II of benzene. The thermodynamic quantities studied here decrease with increasing pressure, as expected, which can be compared with the experimental measurements for the solid phase II of benzene. We find that the Pippard relations are validated within the pressure range considered, in particular, at high pressures for the solid phase II of this molecular crystal.

Calculation of the thermodynamic functions from the Raman frequency shifts close to the 𝜀–δloc–δ transitions and Pippard relations in nitrogen

2020 ◽  
Vol 34 (33) ◽  
pp. 2050382 ◽  
Author(s):  
O. Akay ◽  
H. Yurtseven
Keyword(s):  
Thermodynamic Functions ◽  
Isothermal Compressibility ◽  
Raman Frequency ◽  
Molecular Solids ◽  
Expansion Formula ◽  
Text Data ◽  
Frequency Shifts ◽  
Solid Nitrogen ◽  
Temperature And Pressure ◽  
The Difference

Thermodynamic functions of the thermal expansion [Formula: see text], isothermal compressibility [Formula: see text] and the difference in the heat capacity [Formula: see text] are calculated as a function of temperature ([Formula: see text] GPa) close to the transitions of [Formula: see text][Formula: see text]–[Formula: see text][Formula: see text] and [Formula: see text][Formula: see text]–[Formula: see text][Formula: see text] in the solid nitrogen. This calculation is performed by using the observed Raman frequency shifts of vibrons [Formula: see text] and [Formula: see text]. Also, by using the observed [Formula: see text]–[Formula: see text] data, those thermodynamic functions are predicted at various pressures for the fluid–solid transition in nitrogen. For both calculations, observed data are used from the literature. From the temperature and pressure dependences of the thermodynamic functions studied, the Pippard relations are examined close to the [Formula: see text][Formula: see text]–[Formula: see text][Formula: see text][Formula: see text]–[Formula: see text][Formula: see text] transitions and also fluid–solid transition in nitrogen.We find that the thermodynamic functions can be predicted from the Raman frequency shifts and that the Pippard relations can be established for both the [Formula: see text][Formula: see text]–[Formula: see text][Formula: see text][Formula: see text]–[Formula: see text][Formula: see text] and fluid–solid transitions in nitrogen. This method of predicting the thermodynamic functions can also be applied to some other molecular solids.

scholarly journals Thermodynamic Properties of La1-xSmxCoO3

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Rasna Thakur ◽  
N. K. Gaur
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Bulk Modulus ◽  
Specific Heat ◽  
Specific Heats ◽  
Lattice Specific Heat ◽  
Lattice Distortions ◽  
First Time ◽  
Rigid Ion Model

We have investigated the bulk modulus and thermal properties of La1-xSmxCoO3 (0≤x≤0.2) at temperatures 1 K≤T≤300 K probably for the first time by incorporating the effect of lattice distortions using the modified rigid ion model (MRIM). The calculated specific heat, thermal expansion, bulk modulus, and other thermal properties reproduce well with the available experimental data, implying that MRIM represents properly the nature of the pure and doped cobaltate. The specific heats are found to increase with temperature and decrease with concentration (x) for the present. The increase in Debye temperature (θD) indicates an anomalous softening of the lattice specific heat because increase in T3-term in the specific heat occurs with the decrease of concentration (x).

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