An Equation for Melting and Freezing Transition Rates

1986 ◽  
Vol 74 ◽  
Author(s):  
Philip H. Bucksbaum ◽  
Michael O. Thompson
Keyword(s):  
Large Deviations ◽  
Intermediate State ◽  
Reaction Rate ◽  
Pulsed Laser ◽  
Sharp Interface ◽  
Rate Theory ◽  
Transition Rates ◽  
Laser Melting ◽  
Kinetic Rate ◽  
Melting Experiments

AbstractStatistical thermodynamics is used to derive the reaction rate for melting and freezing by considering an atomically sharp interface with or without an activated intermediate state. The resulting predictions differ substantially from those of the classical kinetic rate theory at large deviations from equilibrium. The model may be appropriate for the analysis of pulsed laser melting experiments where large deviations are expected.

scholarly journals Analysis of Picosecond Pulsed Laser Melted Graphite

1986 ◽  
Vol 74 ◽  
Author(s):  
J. Steinbeck ◽  
G. Braunstein ◽  
J. Speck ◽  
M. S. Dresselhaus ◽  
C. Y. Huang ◽  
...  
Keyword(s):  
Pulsed Laser ◽  
Laser Melting ◽  
Pulse Laser Radiation ◽  
Liquid Carbon ◽  
Additional Information ◽  
Nanosecond Pulsed Laser ◽  
Graphite Crystallite ◽  
Raman Microprobe ◽  
Melting Experiments

AbstractA Raman microprobe and TEM have been used to analyze the resolidified region of liquid carbon generated by picosecond pulse laser radiation. From the relative intensities of the zone center Raman-allowed mode for graphite at 1582cm−1 and the disorder-induced mode at 1360cm−1 , the average graphite crystallite size in the resolidified region is determined as a function of incident pulse energy density. By comparing with Rutherford backscattering spectra and Raman spectra from nanosecond pulsed laser melting experiments, additional information about the disorder depth in picosecond pulsed laser melted graphite is obtained. Comparisons of TEM micrographs for nanosecond and picosecond pulsed laser melting experiments show that the structure of the laser disordered regions in graphite are similar and exhibit similar behavior with increasing laser pulse fluence. The similarities in the resolidified regions under both irradiation schemes discourages a determination of the properties of liquid carbon after the liquid has resolidified.

Thermal Decomposition Kinetics of Glyphosate (GP) and its Metabolite Aminomethylphosphonic Acid (AMPA)

2019 ◽  
Author(s):  
Milad Narimani ◽  
Gabriel da Silva
Keyword(s):  
Thermal Decomposition ◽  
Reaction Rate ◽  
Decomposition Kinetics ◽  
Rate Theory ◽  
Thermal Decomposition Mechanism ◽  
Treatment Processes ◽  
Aminomethylphosphonic Acid ◽  
Reaction Rate Theory ◽  
Decomposition Chemistry ◽  
Kinetics Of

Glyphosate (GP) is a widely used herbicide worldwide, yet accumulation of GP and its main byproduct, aminomethylphosphonic acid (AMPA), in soil and water has raised concerns about its potential effects to human health. Thermal treatment processes are one option for decontaminating material containing GP and AMPA, yet the thermal decomposition chemistry of these compounds remains poorly understood. Here, we have revealed the thermal decomposition mechanism of GP and AMPA by applying computational chemistry and reaction rate theory methods. <br>

scholarly journals The Al Doping Effect on Epitaxial (In,Mn)As Dilute Magnetic Semiconductors Prepared by Ion Implantation and Pulsed Laser Melting

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4138
Author(s):  
Ye Yuan ◽  
Yufang Xie ◽  
Ning Yuan ◽  
Mao Wang ◽  
René Heller ◽  
...  
Keyword(s):  
Curie Temperature ◽  
Ion Implantation ◽  
Diluted Magnetic Semiconductors ◽  
Laser Annealing ◽  
Magnetic Semiconductors ◽  
Dilute Magnetic Semiconductors ◽  
Pulsed Laser ◽  
Laser Melting ◽  
Co Doping ◽  
Diluted Magnetic

One of the most attractive characteristics of diluted ferromagnetic semiconductors is the possibility to modulate their electronic and ferromagnetic properties, coupled by itinerant holes through various means. A prominent example is the modification of Curie temperature and magnetic anisotropy by ion implantation and pulsed laser melting in III–V diluted magnetic semiconductors. In this study, to the best of our knowledge, we performed, for the first time, the co-doping of (In,Mn)As diluted magnetic semiconductors by Al by co-implantation subsequently combined with a pulsed laser annealing technique. Additionally, the structural and magnetic properties were systematically investigated by gradually raising the Al implantation fluence. Unexpectedly, under a well-preserved epitaxial structure, all samples presented weaken Curie temperature, magnetization, as well as uniaxial magnetic anisotropies when more aluminum was involved. Such a phenomenon is probably due to enhanced carrier localization introduced by Al or the suppression of substitutional Mn atoms.

Formation of single crystal sulfur supersaturated silicon based junctions by pulsed laser melting

2007 ◽  
Vol 25 (6) ◽  
pp. 1847 ◽  
Author(s):  
Malek Tabbal ◽  
Taegon Kim ◽  
Jeffrey M. Warrender ◽  
Michael J. Aziz ◽  
B. L. Cardozo ◽  
...  
Keyword(s):  
Single Crystal ◽  
Pulsed Laser ◽  
Laser Melting ◽  
Silicon Based

Pulsed Laser Melting: The Effect of Implanted Solutes on the Resolidification Velocity

1983 ◽  
Vol 23 ◽  
Author(s):  
G. J. Galvin ◽  
J. W. Mayer ◽  
P. S. Peercy
Keyword(s):  
Electrical Conductance ◽  
Pulsed Laser ◽  
Solute Concentration ◽  
Atomic Percent ◽  
Supersaturated Solution ◽  
Solidification Velocity ◽  
Laser Melting ◽  
Solid Interface ◽  
Solution Studies ◽  
Nonequilibrium Segregation

ABSTRACTTransient electrical conductance has been used to measure the resolidification velocity in silicon containing implanted solutes. Nonequilibrium segregation of the solutes occurs during the rapid resolidification following pulsed laser melting. The velocity of the liquid-solid interface is observed to depend on the type and concentration of the solute. A 25% reduction in solidification velocity is observed for an implanted indium concentration of three atomic percent. Implanted oxygen is also shown to reduce the solidification velocity. The dependence of the velocity on solute concentration impacts a variety of segregation, trapping and supersaturated solution studies.

Ab Initio Computation of Thermochemistry and Kinetics in the Oxidation of Gas Phase Silicon Species

1992 ◽  
Vol 282 ◽  
Author(s):  
Michael R. Zachariah ◽  
Wing Tsang
Keyword(s):  
Ab Initio ◽  
Gas Phase ◽  
Energy Barrier ◽  
Reaction Rate ◽  
Rate Theory ◽  
Molecular Orbital Calculations ◽  
Activation Energy Barrier ◽  
Ab Initio Computation ◽  
Oxygen Donor ◽  
Reaction Rate Theory

ABSTRACTAb initio molecular orbital calculations coupled to RRKM reaction rate theory have been conducted on some important reactions involved in the oxidation of silane in a high-temperature/high H2O environment. The results indicate thatH2O acts as an oxygen donor to SiH2 to form H3SiOH or SiH2O. Subsequent reactions involve the formation of (HSiOOH, H2Si(OH)2,:Si(OH)2 or SiO). In turn SiO polymerizes into planar rings, without an activation energy barrier. A list of calculated thermochemical data are also presented for a number of equilibrium species.

Ti-doped Gallium Phosphide Layers with Concentrations Above the Mott Limit

2009 ◽  
Vol 1210 ◽  
Author(s):  
Javier Olea Ariza ◽  
David Pastor ◽  
María Toledano-Luque ◽  
Ignacio Mártil ◽  
Germán González-Díaz ◽  
...  
Keyword(s):  
Gallium Phosphide ◽  
Vibrational Mode ◽  
Pulsed Laser ◽  
X Ray Diffraction ◽  
Laser Melting ◽  
Intermediate Band ◽  
X Ray ◽  
Tof Sims ◽  
Crystalline Domains ◽  
Secondary Ion

AbstractWe have studied the Pulsed-Laser Melting (PLM) effects on Ti implanted GaP to form an Intermediate Band (IB). Structural analysis has been carried out by means of Time of Flight Secondary Ion Mass Spectroscopy (ToF-SIMS), Raman spectroscopy and Glancing Incidence X-Ray Diffraction (GIXRD). After the PLM annealing, Ti concentration is over the Mott limit. Nevertheless, the Raman spectra show a forbidden TO vibrational mode of GaP. This result suggests the formation of crystalline domains with a different orientation in the annealed region regarding to the GaP unannealed substrate. This conclusion has been corroborated by GIXRD measurements. As a result of the polycrystalline lattice, a drop of the mobility is produced.

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