Studies of exciplexes in mixed crystals. Activation energy for solid-state photoaddition proceeding via an exciplex

1982 ◽  
Vol 104 (15) ◽  
pp. 4280-4282 ◽  
Author(s):  
Garry E. Berkovic ◽  
Zvi Ludmer
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Mixed Crystals

A kinetic study of mechanochemical halogen bond formation by in situ31P solid-state NMR spectroscopy

2017 ◽  
Vol 53 (71) ◽  
pp. 9930-9933 ◽  
Author(s):  
Yijue Xu ◽  
Lysiane Champion ◽  
Bulat Gabidullin ◽  
David L. Bryce
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Kinetic Study ◽  
Solid State Nmr ◽  
Halogen Bond ◽  
Bond Formation ◽  
Nmr Studies ◽  
Solid State Nmr Spectroscopy

In situ 31P solid-state NMR studies of mechanochemical halogen bond formation provide insights into the cocrystallisation process and an estimate of the activation energy.

High Tc Oxide Solid State Reaction Kinetics Via Complex Impedance Spectroscopy

1989 ◽  
Vol 169 ◽  
Author(s):  
E. A. Cooper ◽  
T. O. Mason ◽  
U. Balachandran ◽  
M. L. Kullberg
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Solid State ◽  
Solid State Reaction ◽  
Complex Impedance ◽  
Particle Size Effect ◽  
Large Temperature ◽  
Impedance Spectra ◽  
High Tc ◽  
Solid State Reaction Kinetics

AbstractImpedance spectra (5Hz ‐ 13MHz) were collected during the solid state reaction of Yba2Cu2O6+y from large monosized CuO particles imbedded in a finely divided Y2 O3 /BaCO3 matrix. No particle size effect was observed, but a large temperature effect was observed corresponding to an activation energy of approximately 1.8eV (175kJ/mol) over the range 700‐900°C.

scholarly journals Synthesis and Characterisation of Structural and Electrical Properties of CuMn2O4 Spinel Compound

2021 ◽  
pp. 1-4
Author(s):  
Rasha Yousef ◽  
Alaa Nassif ◽  
Abla Al-Zoubi ◽  
Nasser Al-Din
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Electrical Properties ◽  
Optimum Temperature ◽  
Prepared Compound ◽  
Solid State Method ◽  
Structural And Electrical Properties ◽  
Cubic Structure ◽  
Experimental Density ◽  
Scherrer Method

CuMn2O4 was synthesized by the solid-state method. MnO2 and CuO were used as precursors. The optimum temperature of synthesis was 850°C. XRD results showed that the prepared compound had a cubic structure with Fd3 ̅m space group. The lattice constant and unit cell volume were a=8.359Å and V=584.14A°3 respectively. The grain size was calculated by the Debye-Scherrer method and was 33.49 nm for CuMn2O4 annealed at 850°C. The experimental density was calculated and compared to the theoretical density. The results were ρt= 5.399 gr/cm3 and ρE = 5.24 gr/cm3. The electrical properties of the compound showed that it behaves like a semiconductor, and the activation energy of the compound was 0.1535 eV. KEYWORDS Activation energy, copper manganite (CuMO), mixed oxide, solid-state reaction, spinel

Electrical Properties of Fresnoite Ba2TiSi2O8 Using Impedance Spectroscopy

2013 ◽  
Vol 795 ◽  
pp. 640-643 ◽  
Author(s):  
Rozana A.M. Osman ◽  
Mohd Sobri Idris
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Sintering Temperature ◽  
Second Harmonic ◽  
Conventional Solid State Reaction ◽  
Reaction Phase ◽  
Tetragonal Unit Cell ◽  
Phase Pure ◽  
Very High ◽  
Centrosymmetric Structure

Fresnoite with composition Ba2TiSi2O8 (B2TS2) was first found in 1965, adopting a non-centrosymmetric structure. It also reported to crystallize in a tetragonal unit cell with a=8.52Å and c=5.210Å leading to some possible application as hydrophone, transducer and second harmonic generation and low temperature co-fired ceramics (LTCC). B2TS2 were synthesized by conventional solid state reaction. Phase pure B2TS2 was obtained after heating the pellets at a final sintering temperature of 1230 °C in air at 92 h. Study found that Fresnoite B2TS2 is a type of materials which are not ferroelectric and instead show perfect dielectric insulator behaviour with resistance >106Ωcm at temperatures below 750°C and also shows nonideal debye respone. The activation energy for conduction of B2TS2 samples is very high, indicating that these materials are highly insulating.

scholarly journals Kinetics of the Volume Shrinkage of a Magnetite/Carbon Composite Pellet during Solid-State Carbothermic Reduction

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1050 ◽  
Author(s):  
Guang Wang ◽  
Jingsong Wang ◽  
Qingguo Xue
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Apparent Activation Energy ◽  
Carbothermic Reduction ◽  
Iron Ore ◽  
Carbon Composite ◽  
Volume Shrinkage ◽  
Reduction Temperature ◽  
Iron Particles ◽  
Composite Pellet

The volume shrinkage evolution of a magnetite iron ore/carbon composite pellet during solid-state isothermal reduction was investigated. For the shrinkage, the apparent activation energy and mechanism were obtained based on the experimental results. It was found that the volume shrinkage highly depended on the reduction temperature and on dwell time. The volume shrinkage of the pellet increased with the increasing reduction temperature, and the rate of increment was fast during the first 20 min of reduction. The shrinkage of the composite pellet was mainly due to the weight loss of carbon and oxygen, the sintering growth of gangue oxides and metallic iron particles, and the partial melting of the gangue phase at high temperature. The shrinkage apparent activation energy was different depending on the time range. During the first 20 min, the shrinkage apparent activation energy was 51,313 J/mol. After the first 20 min, the apparent activation energy for the volume shrinkage was only 19,697 J/mol. The change of the reduction rate-controlling step and the automatic sintering and reconstruction of the metallic iron particles and gangue oxides in the later reduction stage were the main reasons for the aforementioned time-dependent phenomena. The present work could provide a unique scientific index for the illustration of iron ore/carbon composite pellet behavior during solid-state carbothermic reduction.

A simple method of determining the activation energy of an isothermal solid-state decomposition reaction

1980 ◽  
Vol 18 (1) ◽  
pp. 185-191 ◽  
Author(s):  
S. R. Dharwadkar ◽  
A. B. Phadnis ◽  
M. S. Chandrasekharaiah ◽  
M. D. Karkhanavala
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Decomposition Reaction ◽  
Simple Method ◽  
Solid State Decomposition
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