Structural Phase Transitions I [Paperback]

With contributions by numerous experts1. Introduction.- References.- 2. Optical Studies of Structural Phase Transitions.- 2.1 Background.- 2.1.1 Phase Transitions in Solids: Definitions.- 2.1.2 Symmetry Classification of Optical Techniques.- 2.2 Experimental Techniques.- 2.2.1 Absorption and Fluorescence.- a) IR Absorption and Reflection.- b) Optical Absorption and Fluorescence.- 2.2.2 Birefringence.- a) Typical Experimental Apparatus.- 2.2.3 Light Scattering.- a) General Background.- b) Scattering from Coupled Modes.- c) Critical Exponents and Soft Mode Spectra.- d) Intensity of Scattering.- e) Grating Spectroscopy.- f) Interferometry.- g) Recent Advances of Technique.- 2.3 Ferroelastic Transitions.- 2.3.1 Cooperative Jahn-Teller Systems.- 2.3.2 PrAlO3: A Prototypical CJT System.- 2.4 Nonpiezoelectric Ferroelectric: Pb5Ge3O11.- 2.5 Piezoelectric-Ferroelectric Transition in KDP and Its Isomorphs.- 2.5.1 Coupled Modes i n the Raman Spectrum.- 2.5.2 Brillouin-Raman Spectra.- 2.5.3 Static and Dynamic Central Peaks.- 2.6 Zone Boundary Phase Transitions (Antiferrodistortive).- 2.6.1 Systematics in the Fluoroperovskites.- 2.6.2 Recent Results in SrTiO3.- 2.7 Zone Boundary Ferroelectrics: The Molybdates.- 2.8 Incommensurate Phase Transitions.- 2.8.1 Charge-Density Waves: TaSe2.- 2.8.2 Incommensurate-Ferroelectric: K2SeO4.- 2.8.3 Ferroelectric-Antiferroelectric: BaMnF4.- 2.9 Nonlinear Optical Studies of Phase Transitions.- 2.10 Renormalization Group Theory and Multicritical Phenomena.- 2.11 Concluding Remarks.- References.- 3. Investigation of Structural Phase Transformations by Inelastic Neutron Scattering.- 3.1 Inelastic Neutron Scattering.- 3.1.1 General Aspects.- 3.1.2 Structural Changes with Small Displacements.- 3.1.3 Soft Modes.- 3.2 The Central-Peak Phenomenon.- 3.3 Molecular Crystals.- 3.3.1 The Elastic Incoherent Structure Factor (EISF).- 3.3.2 High-Resolution Instruments.- a) The Backscatteri ng Spectrometer.- b) The Four Chopper Time-of-Flight Spectrometer.- c) l³°