Experimental investigations and numerical integration of the thermally stimulated current rate equations for defect parameters in CdTe crystals

1987 ◽  
Vol 61 (6) ◽  
pp. 2230-2233 ◽  
Author(s):  
S. G. Elkomoss ◽  
M. Samimi ◽  
S. Unamuno ◽  
M. Hage‐Ali ◽  
P. Siffert
Keyword(s):  
Numerical Integration ◽  
Rate Equations ◽  
Experimental Investigations ◽  
Thermally Stimulated Current

scholarly journals Combining simulation to nonlinear fitting for the determination of rate constants of elementary reactions by using Excel spreadsheets

2012 ◽  
Vol 8 (4) ◽  
Author(s):  
Ammar M. Tighezza ◽  
Daifallah M. Aldhayan ◽  
Nouir A. Aldawsari
Keyword(s):  
Experimental Data ◽  
Numerical Integration ◽  
Chemical Kinetics ◽  
Chemical Reactions ◽  
Rate Constants ◽  
Model Equation ◽  
Rate Equations ◽  
Unknown Parameters ◽  
Elementary Reactions ◽  
Nonlinear Fitting

A common problem in chemistry is to determine parameters (constants) in an equation used to represent experimental data. Examples are fitting a set of data to a model equation (straight line or curve) to obtain unknown parameters. In chemical kinetics, a set of data is usually a number of concentrations versus time, but the model equation is not well defined! Instead of a well defined model equation we have a set of coupled ODE’s (ordinary differential equations) which represent rate equations for reactants and products. The analytical integration of these ODE’s is rarely possible. The numerical integration is the alternative. In this work are combined the simulation of chemical reactions, by using numerical integration, and nonlinear regression (curve fitting) by using “Solver add-in” of Microsoft Excel to find rate constants of elementary reactions from experimental data. This method is illustrated on three complex mechanisms. The simulation of chemical reactions in Excel spreadsheets is illustrated with/without VBA programming. The automation (automatic obtaining of rate equations from mechanism: no need of chemical kinetics knowledge from the end user!) of mechanism simulation is demonstrated on many example.

scholarly journals Analysis of progress curves by simulations generated by numerical integration

1989 ◽  
Vol 258 (2) ◽  
pp. 381-387 ◽  
Author(s):  
C T Zimmerle ◽  
C Frieden
Keyword(s):  
Computer Program ◽  
Numerical Integration ◽  
Rate Constants ◽  
Weighted Least Squares ◽  
Rate Equations ◽  
Kinetic Rate ◽  
Fitting Procedure ◽  
Progress Curve ◽  
Kinetic Rate Constants ◽  
Simulated Test

A highly flexible computer program written in FORTRAN is presented which fits computer-generated simulations to experimental progress-curve data by an iterative non-linear weighted least-squares procedure. This fitting procedure allows kinetic rate constants to be determined from the experimental progress curves. Although the numerical integration of the rate equations by a previously described method [Barshop, Wrenn & Frieden (1983) Anal. Biochem. 130, 134-145] is used here to generate predicted curves, any routine capable of the integration of a set of differential equations can be used. The fitting program described is designed to be widely applicable, easy to learn and convenient to use. The use, behaviour and power of the program is explored by using simulated test data.

Rate of Reaction of OH with HCN Between 298 and 563 K

1979 ◽  
Vol 32 (12) ◽  
pp. 2571 ◽  
Author(s):  
LF Phillips
Keyword(s):  
Numerical Integration ◽  
Rate Constant ◽  
Flow System ◽  
Rate Equations ◽  
Side Reactions ◽  
Resonance Fluorescence ◽  
Discharge Flow ◽  
Temperature Range ◽  
Rate Of Reaction ◽  
Estimated Error

Hyroxyl resonance fluorescence was used to study the reaction of OH with HCN in a discharge-flow system. The effect of side reactions involving OH was assessed by numerical integration of the rate equations for the system. The rate constant for the reaction: OH + HCN → products as measured at pressures above 10 Torr and under conditions where side reactions were believed to be unimportant, is given by the expression: k = 1.60 ° 10-11 T-1exp(-1.86 × 103/T) cm3 molecule -1 s-1 with an estimated error of � 20% over the temperature range from 298 to 563 K.

Experimental investigations and rate equations of quasi-continuous-wave laser operation of titanium-doped sapphire

1993 ◽  
Author(s):  
Jianquan Yao ◽  
Xinglong Wang ◽  
Changqing Wang ◽  
Jingping Ning ◽  
Xiaojun Fang ◽  
...  
Keyword(s):  
Continuous Wave ◽  
Rate Equations ◽  
Experimental Investigations ◽  
Laser Operation ◽  
Continuous Wave Laser ◽  
Wave Laser

Thermally-Stimulated Currents in Thin-Film Semiconductors: Analysis and Modelling

2006 ◽  
Vol 910 ◽  
Author(s):  
Charles Main ◽  
Nacera Souffi ◽  
Steve Reynolds ◽  
Zdravka Aneva ◽  
Rudi Brüggemann ◽  
...  
Keyword(s):  
Thin Film ◽  
Carrier Lifetime ◽  
Linear Time ◽  
Time Dependent ◽  
Rate Equations ◽  
Conductivity Data ◽  
Thermally Stimulated Current ◽  
Dependent Rate ◽  
Wide Range ◽  
Thin Film Semiconductors

AbstractThis paper investigates the robustness of the thermally stimulated current technique as a method to determine the density of states distribution in thin film semiconductors under a wide range of conditions. Numerical simulation is used to solve the non-linear time-dependent rate equations for free and trapped charge in systems with continuous and structured DOS profiles. We explore the derivation of energy and density scales from temperature and conductivity data. We examine for these systems the limits of the method's apparent immunity to varying conditions of strong and weak retrapping, and investigate the corrections required for variations in carrier lifetime with temperature.

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