Structural Phase Transition in Lysozyme Single Crystals
Teslyuk I., Nastishin Yu., Vlokh R.
Institute of Physical Optics, 23 Dragomanov St., 79005
Lviv, Ukraine
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Polarization microscopy observations of the lysozyme single crystals
in the 4C–40C region are represented. The interference colours of the crystal
texture observed between crossed polarizers drastically change at TC=11C
unambiguously displaying a phase transition. The temperature dependence
of the birefringence deduced from these observations indicates that the
phase transition is of strongly first order. The low-temperature (T<11
C) phase intensively scatters light. The phase transition is accompanied
by the deformation (about 5%) of the crystal. The observed textural changes
are reversible in temperature. We argue that the phase transition is of
a ferroelastic type and the low-temperature (T<11C) phase might be of
a ferroelastic type with symmetry 222 or one of two ferroelectric-ferroelastic
types of symmetries 2 or 1.
PACS: 78.20.Fm, 77.84, 64.70.Kb
Key words: biocrystals, lysozyme, phase transition, ferroelasticity,
optical birefringence
doi 10.3116/16091833/5/4/118/2004 |
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