Structural phase transition

The sample eapsule is plaeed in a tight-fitting 4340 steel fixture that serves to support the eopper eapsule. Pressure from the detonation of the explosive is transmitted to the eopper eapsule through a mild steel driver plate. This plate is also lapped optically flat on both surfaces. The mild steel acts to shape the pressure pulse due to the 13 GPa structural phase transition. With proper choice of the diameter of the driver plate and beveled interior opening of the steel fixture, shock deformation of the driver plate acts to seal the capsule within the fixture. 

Many interesting quantum effects appear at low temperatures due to the effect of quantum statistics. Very interesting PIMC studies of such effects have been done for structural phase transitions in adsorbed " He and He layers [90-91] and for the superfluidity of H2 layers [92]. For studies of related systems and additional information see Sec. IV D 2. 

A. D. Bruce and R.A. Cowley, Structural phase transitions III. Critical dynamics and... 

Kondo, Y, Ru, Q. and Takayanagi, K. (1999) Thickness Induced Structural Phase Transition of Gold Nanofilm. Physical Review Letters, 82, 751—754. 

International Tables for Crystallography, Vol. D Physical Properties of Crystals (A. Authier, ed.), Chapter 3.1 (J.-C. Toledano, V. Janovec, V. Kospky, J. F. Scott, P. Boek) Structural phase transitions. Kluwer, 2003. 

Smith, G. R. Bruce, A. D., Multicanonical Monte Carlo study of a structural phase transition, Europhys. Lett. 1996, 34, 91-96... 

The structural phase transitions and nature of the Br... N and Br... Br interactions in l-phenyl-2-methyl-4-nitro-5-bromoimidazole have been studied [76], The compound was found to undergo a reversible order-disorder transition over a wide... 

XRD MFI structure orthorhombic (Pnma space group at room temperature) to monoclinic (P2j/n space group at low temperatures) structural phase transition... 

A basic concept in the reconstruction theory of solid surfaces is the soft phonon approach of displacive structural transitions. An essential property of these structural phase transitions is the existence of an order parameter which... 

If excess specific heat, defined as that part of the specific heat that is due to the structural phase transition (cf Salje, 1988), is denoted by ACpexcess,trans> the excess entropy associated with transition within the upper and lower limits of Cp perturbation is given by... 

Salje E. (1988). Structural phase transitions and specific heat anomalies. In Physical Properties and Thermodynamic Behaviour of Minerals, E. K. H. Salje, ed. Reidel Pnblishing Company. 

Experimental studies on the thermal decomposition and combushon processes of AP have been carried out and their detailed mechanisms have been reported.P-iil Fig. 5.1 shows the thermal decomposition of AP as measured by differential thermal analysis (DTA) and thermal gravimetry (TG) at a heating rate of 0.33 K s"f An endothermic peak is seen at 520 K, corresponding to an orthorhombic to cubic lattice crystal structure phase transition, the heat of reaction for which amounts to... 

The structural phase transition for a quantum paraelectric was handled by the following model Hamiltonian [2] ... 

In order to understand our NMR spin-lattice relaxation experiments we have to revisit some basic features of structural phase transitions. 

Emge TJ, Leung PCW, Beno MA, Schultz AJ, Wang HH, Sowa LM, Williams JM (1984) Neutron and X-ray diffraction evidence for a structural phase transition in the sulfur-based ambient-pressure organic superconductor bis(ethylenedithio)tetrathiafulvalene triiodide. Phys Rev B30 6780-6782... 

Horie, Y., Fukami, T. and Mase, S., First Order Structural Phase Transition in BaPbj B Og and the Scaling Law. Solid State Comm. 62(7) 471 (1987). 

An interesting aspect of many structural phase transitions is the coupling of the primary order parameter to a secondary order parameter. In transitions of molecular crystals, the order parameter is coupled with reorientational or libration modes. In Jahn-Teller as well as ferroelastic transitions, an optical phonon or an electronic excitation is coupled with strain (acoustic phonon). In antiferrodistortive transitions, a zone-boundary phonon (primary order parameter) can induce spontaneous polarization (secondary order parameter). Magnetic resonance and vibrational spectroscopic methods provide valuable information on static as well as dynamic processes occurring during a transition (Owens et ai, 1979 Iqbal Owens, 1984 Rao, 1993). Complementary information is provided by diffraction methods. 

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