Critical behavior of the disorder-induced Raman modes close to the lambda-phase transition in NH4Cl

Date

2002-06-01

Author

Yurtseven, Hasan Hamit

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This study gives our analysis of the disorder-induced Raman modes of v(7) (93 cm(-1)) and v. (144 cm(-1)) close to the lambda-phase transition (P = 0) in the NH4Cl crystal. We describe the critical behavior of the frequency shifts for those modes by a power-law formula and using our Raman data we obtain the value of 0.1 for the critical exponent which can also describe the critical behavior of the thermal expansivity and the specific heat of NH4Cl Close to its A-phase transition (T-lambda = 242.9 K).

Subject Keywords

Raman modest, Lambda-transition, NH4Cl

URI

https://hdl.handle.net/11511/56809

Journal

SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY

DOI

https://doi.org/10.1016/s1386-1425(01)00632-1

Collections

Department of Physics, Article

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Critical behaviour of the thermodynamic quantities close to phase transitions in molecular crystals using raman data Özdemir, Hilal; Yurtseven, Hasan Hamit; Department of Physics (2017) In this thesis we investigate the pressure and temperature dependence of the Raman frequencies for diffirent modes of benzene at ambient conditions (P=0 GPa and T=300 K). By using the experimental data we calculated the volume and frequency as a function of pressure at constant temperature and as a function of temperature at constant pressure, thus isothermal and isobaric mode Grüneisen parameter has been inferred in the diffrent modes. Our calculations show that calculated Raman frequencies agree well with...

Citation Formats

H. H. Yurtseven, “Critical behavior of the disorder-induced Raman modes close to the lambda-phase transition in NH4Cl,” SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, pp. 1823–1830, 2002, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/56809.