Correlation of Structure with Crystalline to Amorphous Phase Transitions of 1,3,6-Substituted Fulvene-Derived Molecular Glasses

2020 ◽  
Vol 85 (17) ◽  
pp. 11116-11123
Author(s):  
Loren C. Brown ◽  
Andrew J. Peloquin ◽  
Nicholas P. Godman ◽  
Gary J. Balaich ◽  
Scott T. Iacono
Keyword(s):  
Phase Transitions ◽  
Amorphous Phase ◽  
Molecular Glasses

Two Species/Nonideal Solution Model for Amorphous/Amorphous Phase Transitions

1996 ◽  
Vol 455 ◽  
Author(s):  
Cornelius T. Moynihan
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Critical Temperature ◽  
Amorphous Phase ◽  
Thermodynamic Model ◽  
Critical Pressure ◽  
Solution Model ◽  
Amorphous Phases ◽  
First Order ◽  
Temperature And Pressure

ABSTRACTA simple macroscopic thermodynamic model for first order transitions between two amorphous phases in a one component liquid is reviewed, augmented and evaluated. The model presumes the existence in the liquid of two species, whose concentrations are temperature and pressure dependent and which form a solution with large, positive deviations from ideality. Application of the model to recent data indicates that water can undergo an amorphous/amorphous phase transition below a critical temperature Tc of 217K and above a critical pressure Pc of 380 atm.

Applications Of Crystalline-amorphous Phase Transitions In Silicon Carbide

2005 ◽  
Author(s):  
C. Wagner ◽  
G. Krotz ◽  
H. Sonntag ◽  
H. Muller ◽  
G. Midler ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Phase Transitions ◽  
Amorphous Phase

Crystal structure of a 1,6-bis(phenylethynyl)pyrene-based cyclophane that exhibits mechanochromic luminescence

2021 ◽  
Author(s):  
Shohei Simizu ◽  
Shakkeeb Thazhathethil ◽  
Kiyonori Takahashi ◽  
Takayoshi Nakamura ◽  
Yoshimitsu Sagara
Keyword(s):  
Crystal Structure ◽  
Phase Transitions ◽  
Amorphous Phase ◽  
Photophysical Properties ◽  
Luminescent Materials ◽  
Mechanical Stimuli ◽  
Stimuli Responsive ◽  
Mechanochromic Luminescence

Cyclophanes featuring luminophores are considered promising candidates as thermal or mechanical stimuli-responsive luminescent materials. The mechanism of the changes in the photophysical properties on the crystal-crystal or crystal-amorphous phase transitions...

The Environment-Dependent Interatomic Potential Applied To Silicon Disordered Structures And Phase Transitions

1997 ◽  
Vol 491 ◽  
Author(s):  
Martin Z. Bazant ◽  
Efthimios Kaxiras ◽  
J. F. Justo
Keyword(s):  
Phase Transitions ◽  
Ab Initio ◽  
Amorphous Phase ◽  
Functional Form ◽  
Interatomic Potential ◽  
Amorphous Structure ◽  
Empirical Potential ◽  
Disordered Structures ◽  
Metallic Bonding ◽  
Environment Dependence

ABSTRACTThe recently developed Environment-Dependent Interatomic Potential (EDIP) holds the promise of a new degree of transferability in describing bulk phases and defects of elemental covalent solids with a simple theoretically motivated functional form. Here we explore to what extent the environment-dependence of the model can extrapolate successes of the fitted version for Si for bulk defects to disordered phases, which involve local configurations very different from those used in fitting. We find that EDIP-Si provides an improved description of the metallic bonding bond angles of the liquid and is the first empirical potential to predict a quench directly from the liquid to the amorphous phase. The resulting amorphous structure is in closer agreement with ab initio and experimental results than with any artificial prepration method. We also show that melting of the bulk crystal and premelting of the (100)2×1 surface are reasonably well described by EDIP-Si in spite of its not being fit to any such properties.

Electron Microscopy of Graphite Intercalation Compounds

1982 ◽  
Vol 40 ◽  
pp. 544-545
Author(s):  
G. Timp ◽  
L. Salamanca-Riba ◽  
L.W. Hobbs ◽  
G. Dresselhaus ◽  
M.S. Dresselhaus
Keyword(s):  
Electron Microscopy ◽  
Phase Transitions ◽  
Domain Wall ◽  
Intercalation Compounds ◽  
Lattice Plane ◽  
Wall Model ◽  
Graphite Intercalation Compounds ◽  
Fundamental Symmetry ◽  
Graphite Intercalation

Electron microscopy can be used to study structures and phase transitions occurring in graphite intercalations compounds. The fundamental symmetry in graphite intercalation compounds is the staging periodicity whereby each intercalate layer is separated by n graphite layers, n denoting the stage index. The currently accepted model for intercalation proposed by Herold and Daumas assumes that the sample contains equal amounts of intercalant between any two graphite layers and staged regions are confined to domains. Specifically, in a stage 2 compound, the Herold-Daumas domain wall model predicts a pleated lattice plane structure.

Multiple phase transitions investigated by high-speed TEM

1990 ◽  
Vol 48 (4) ◽  
pp. 550-551
Author(s):  
Oleg Bostanjoglo ◽  
Peter Thomsen-Schmidt
Keyword(s):  
Phase Transitions ◽  
High Speed ◽  
Short Exposure ◽  
Semiconductor Film ◽  
Time Resolved ◽  
Short Exposure Time ◽  
Multiple Phase ◽  
Model Substance ◽  
History Of ◽  
Electron Image

Thin GexTe1-x (x = 0.15-0.8) were studied as a model substance of a composite semiconductor film, in addition being of interest for optical storage material. Two complementary modes of time-resolved TEM were used to trace the phase transitions, induced by an attached Q-switched (50 ns FWHM) and frequency doubled (532 nm) Nd:YAG laser. The laser radiation was focused onto the specimen within the TEM to a 20 μm spot (FWHM). Discrete intermediate states were visualized by short-exposure time doubleframe imaging /1,2/. The full history of a transformation was gained by tracking the electron image intensity with photomultiplier and storage oscilloscopes (space/time resolution 100 nm/3 ns) /3/. In order to avoid radiation damage by the probing electron beam to detector and specimen, the beam is pulsed in this continuous mode of time-resolved TEM,too.Short events ( <2 μs) are followed by illuminating with an extended single electron pulse (fig. 1c)

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