Negative evidence for a proton-tunneling mechanism in the phase transition of KH2PO4-type crystals
Abstract
We have found a linear relation between the transition temperature T sub c (in K) and the hydrogen-bond length R (in Å) for tetragonal KH2PO4-type crystals, Tc=2290(R-2.428), irrespective of whether the crystals are deuterated or undeuterated; this finding supplies negative evidence for the proton-tunneling mechanism in the phase transition. We deduce from this relation that the isotope effect in the initial pressure derivative of Tc, dTc/dp, reflects not the isotope effect in dTc/dR, so far regarded as supporting evidence of proton tunneling, but that of dR/dp. Some R and dR/dp values at Tc are predicted.
- Publication:
-
Physical Review B
- Pub Date:
- July 1987
- DOI:
- 10.1103/PhysRevB.36.874
- Bibcode:
- 1987PhRvB..36..874I
- Keywords:
-
- 77.80.Bh;
- 64.70.Kb;
- Phase transitions and Curie point;
- Solid-solid transitions