Calculation of the Raman frequencies and thermodynamic quantities at high pressures for the cubic gauche nitrogen (cg-N)

YURTSEVEN H. H., AKAY SEFER Ö.

Journal of Molecular Structure, cilt.1294, 2023 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 1294
  • Basım Tarihi: 2023
  • Doi Numarası: 10.1016/j.molstruc.2023.136495
  • Dergi Adı: Journal of Molecular Structure
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, Chimica, Compendex, INSPEC
  • Anahtar Kelimeler: cg-N structure, Mode Grüneisen parameter, Raman frequencies, Thermodynamic quantities, υ-P relation
  • Marmara Üniversitesi Adresli: Evet

Özet

This study gives the calculation of the frequencies from the V-P Vinet EOS which has been modified as the frequency-pressure (υ-P) relation for the spectroscopic parameters in the cubic gauche nitrogen(cg-N). Calculation of the Raman frequencies is performed by means of the mode Grüneisen parameter as a function of pressure for the cg-N phase. From the Raman frequencies calculated, the pressure dependence of the thermodynamic quantities such as the free energy, entropy, heat capacity and the enthalpy are predicted by using the quasi-harmonic approximation for the cg-N structure. Our results show that the υ-P relation derived from the V-P relation (Vinet-EOS) can be used to predict the frequencies and that the quasi-harmonic approximation is satisfactory to predict the thermodynamic quantities of interest, as exemplified for the cg-N structure in this study.