Journal of Physical Studies 13(2), Article 2703 [6 pages] (2009)
DOI: https://doi.org/10.30970/jps.13.2703

EQUILIBRIUM STATES AND PHASE TRANSITIONS IN HYDROGEN-BONDED MOLECULAR AND CRYSTAL STRUCTURES

R. Ya. Stetsiv¹, R. Ya. Yurechko²
¹Institute for Condensed Matter Physics National Academy of Sciences of Ukraine,
1, Svientsitskii St., Lviv, UA--79011, Ukraine
²National University ‟Lvivska Politekhnika”,
12, Bandera St., Lviv, UA--79013, Ukraine

The possibility of the first- or second-order transitions from uniform phase into that with doubled lattice period in the quasi-one-dimensional structures with hydrogen bonds is studied in the framework of proposed pseudospin-electron model. The dependence of the electron concentration and mean number of protons on site on temperature and asymmetry field were obtained. It was shown that abrupt changes of these characteristics at the first-order transitions is smaller for the structures with a high proton tunnelling frequency. The equation for the second-order phase transition temperature is obtained. The electron spectrum is calculated. The dependence of the splitting of the electron spectrum on temperature and asymmetry field is investigated.

PACS number(s): 72.60.+g, 36.40.-c