Temperature Dependence of the Entropy and the Heat Capacity Calculated from the Raman Frequency Shifts for Solid Benzene, Naphthalene and Anthracene

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Yurtseven H., Ozdemir H.

INTERNATIONAL JOURNAL OF THERMODYNAMICS, cilt.25, sa.3, ss.55-62, 2022 (ESCI) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 25 Sayı: 3
  • Basım Tarihi: 2022
  • Doi Numarası: 10.5541/ijot.1108782
  • Dergi Adı: INTERNATIONAL JOURNAL OF THERMODYNAMICS
  • Derginin Tarandığı İndeksler: Emerging Sources Citation Index (ESCI), Scopus, Applied Science & Technology Source, Compendex, Computer & Applied Sciences
  • Sayfa Sayıları: ss.55-62
  • Anahtar Kelimeler: Quasiharmonic approach, free energy, entropy, heat capacity, PRESSURE-DEPENDENCE, PHASE-TRANSITION, X-RAY, THERMAL-CONDUCTIVITY, DYNAMICS, VOLUME, TRANSFORMATION, POINT, MODES
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

Temperature dependences of the free energy (F), entropy (S) and the heat capacity (????????????) are calculated (P=0) for the organic compounds (solid benzene, naphthalene and anthracene) by using the quasiharmonic approximation. Contributions to those thermodynamic functions due to the Raman frequencies of lattice modes (solid benzene), librational modes (naphthalene), phonons and vibrons (anthracene) are taken into account in our calculations. We obtain that similar linear increase of F and nonlinear increase of S and ????????????, occur with the increasing temperature in benzene and naphthalene. This linear (F) and nonlinear (S, ????????????) increase is rather different for anthracene as the molecular structure becomes complex (benzene-naphthalene-anthracene), as expected. Our calculations by the quasiharmonic approximation can be compared with the experiments for those organic compounds.