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.

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.

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.

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.

scholarly journals The Thermal Expansion of Solids

1959 ◽  
Vol 12 (3) ◽  
pp. 237 ◽  
Author(s):  
GC Fletcher
Keyword(s):  
Thermal Expansion ◽  
Sodium Chloride ◽  
Equation Of State ◽  
Specific Heat ◽  
High Temperatures ◽  
Isothermal Compressibility ◽  
Constant Volume ◽  
Normal Vibrations ◽  
Ionic Solid ◽  
Theory And Experiment

From the theory of normal vibrations of a lattice, a practical means of obtaining the equation of state of an ionic solid is developed from which the thermal expansion can be derived. Using previous work by Kellermann, application is made to the case of sodium chloride and the results compared with experiment. Possible reasons for the discrepancy between theory and experiment, which is very large at 'high temperatures, are discussed. The variation with temperature of the specific heat at constant volume and the isothermal compressibility are also investigated.

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