Release Notes


A Calculational Database for Unimolecular Reaction

Vladimir Mokrushin, Wing Tsang
National Institute of Standards and Technology Gaithersburg, MD 20899, U.S.A.

Click on the link below to download free evaluation version of ChemRate.
ChemRate 1.5.8 9.2MB 07/29/2009
ChemRate 1.5.2 8.9MB 08/23/2006


ChemRate is a program that contains databases containing experimental results on unimolecular reactions, information pertaining to transition state and  molecular structures necessary for the calculation of high pressure rate constants and thermal functions respectively. It contains a master equation solver so that rate constants for unimolecular reactions in the energy transfer region and chemical activation processes under steady and non-steady state conditions can be determined on the basis of RRKM theory.
Flow Sheet for The Calculation of Unimolecular Reactions
Databases of Transition States
and Molecular Properties
  Databases for Experimental Results
Calculator for Density and
Sum of States Specific Rates
  Calculator for High Pressure
Rate Constants Thermal Functions
Master Equation Solver
Distribution Functions
Rate Constants for All Conditions
Curve Fitting Routines
Appropriate Forms for Simulation


  • Calculates high pressure  rate constants of all  unimolecular reactions on the basis of transition state theory.
  • Determines specific rate constants on the basis of RRKM theory.
  • Treats multichannel reactions including chemical activation processes under equilibrium and non-equilibrium conditions. Calculates steady state rate constant as well as time-dependent rate constants.
  • Carry out calculations with any initial distribution.
  • Compute thermofunctions (Cp, D , D, pK, etc.) at any temperature.
  • Simple treatment of bimolecular reactions.
  • Calculates thermodynamic properties and rate constants from Gaussian file.
  • Treats hindered rotors.
  • Treats tunneling.
  • Multicomponent buffer gas.
  • Fit computed results in various ways.
  • Compare computed results with experimental data.
  • Easy to build time-dependent distribution functions, rate constants, and concentration.
  • Creates and accesses the database of components and reactions. The database includes: standard heat of formation, frequencies, external and internal rotations, collision parameters, geometry, experimental data. Possibility to define collisional parameters between any pair of collision participants.
Application contains follow tools:
  • Content-sensitive help.
  • 3D molecule geometry viewer.
  • Import data from GAUSSIAN output file.
  • Find internal rotors and compute moments of inertia.
  • Compute Lenard-Jones parameters from critical T and P.
  • Graphical presentation of data including 3D view.
  • Data exchange between other Windows applications (Word, Excel, Access, etc.) by copy & paste.
  • Pentium II 400 processor
  • Windows 95/98/NT/2000/XP
  • 128 Mb RAM
  • 100 Mb hard drive space


Workspace Image
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Database Image
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Copyright © 2009 Mokrushin Software. All rights reserved.