Phase transformations in locally anharmonic systems. Susceptibility approach to orientational instabilities in molecular solids

• Autorzy: Kuchta B. , Luty T.
• Języki publikacji: EN

Abstrakty

EN

A model of the structural transformation has been discussed, where the local potential is anharmonic but single-welled. Such potential representants a Hamiltonian to model the structural phase transition in charge-transfer molecular crystals A-TCNB (anthracene-tetracyanobenzene). The conditions for the instability and transformation have been found, using the static susceptibility approach, and compared with the variational approximation. The latter method gives a six times lower transition temperature. The fluctuations and entropy are pointed out as the cause of this difference. The exact transition temperature has been calculated by simple Monte Carlo simulations. A comparison with a double-welled case, which models the structural transition in N-TCNB molecular crystal (naphthalene-tetracyanobenzene), has been presented.

Słowa kluczowe

EN

phase transition; simulation; charge transfer; molecular crystal

• Wydawca: Polskie Towarzystwo Chemiczne
• Czasopismo: Polish Journal of Chemistry
• Rocznik: 1998
• Tom: Vol. 72, nr 2
• Strony: 426--432
• Opis fizyczny: Bibliogr. 12 poz., wykr.

Twórcy

autor

Kuchta B.

autor

Luty T.

• Institute of Physical and Theoretical Chemistry Technical University of Wrocław Wybrzeże Wyspiańskiego 27 50-370 Wrocław Poland