Title: TRANSITION TEMPERATURE IN KDP TYPE CRYSTALS UNDER EXTERNAL PRESSURES. ROLE OF H-BOND GEOMETRY
Authors: R.R.Levitskii, A.P.Moina (Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Str., 79011 Lviv, Ukraine), I.R.Zachek (State University ``Lviv Polytechnics'', 13 Bandery Str., 290000, Lviv, Ukraine)

Within the four-particle cluster approximation for the proton ordering model, we study effects of external pressures which do not lower the symmetry of crystals on deuterated ferroelectrics and antiferroelectrics of \kdp\ family. We show that the universality of the transition temperature vs D-site distance dependence observed experimentally in some of the crystals deformed by hydrostatic pressure is also obeyed by the other crystals of the family as well as under the uniaxial pressure $p=-\sigma_3$.

Comments: Figs. 2, Refs. 20, Tabs. 1.