What's New
Graphical Interface


As of February 2023, the Kintecus simulation software has been cited  over 600+ peer reviewed high impact factor journals: SCIENCE, JACS, PNAS, J. Phys. Chem.A, NATURE, PCCP, J. Biol. Chem., Plas. Chem. Plas. Proc., Int. J. Chem. React. Tech, Arch. Bio. Chem. Bio. Phys., THEOCHEM, and many others. 
As of 2022, Kintecus has been getting one citation every 4 to 5 days .
Click the Cites-Papers button on the left side to see some.

Academic/Educational users can now apply for free Kintecus and ATROPOS license keys too.
Click Academic Reg for further details.

What's New -

Kintecus version 2021 has been released. For full details please see the What's New page:

  • *NEW* For accurate chemical mechanism determination and rate constant fitting and regression, all methods listed in Stanbury and Hoffman's 2019 paper "Systematic Application of the Principle of Detailed Balancing to Complex Homogeneous Chemical Reaction Mechanisms" are NOW included in Kintecus. It appears that given a valid chemical mechanism, such a mechanism might be invalid even though the chemical mechanism may make "chemical sense". Kintecus will perform this analysis thoroughly and automatically within itself simply by adding the "-MECHV" switch on the Kintecus command line! Much more details in the manual....
  • The option of holding concentrations/temperatures/pressure constant between datasets for global regression runs. In earlier versions of Kintecus, one could set initial conditions for each experimental dataset. These initial conditions could change during a global regression run. One can now hold this initial condition constant for each experimental dataset. For example, suppose one performed regression with many datasets with different initial conditions for each experiment (such as pH). In that case, one can now set pH values (or temperature or any other value) to different starting constant values for each run in the initial condition file, and that value will not change. It is possible to have different constant initial values for each regressed.
  •  A new "validate" feature. This feature will allow one to compare a single Kintecus run against an external synthetic/experimental dataset. This feature (invoked by adding the "-validate:<datafile name>" flag on the command line) will force Kintecus to match exactly all timings and conditions against this externally calculated or measured dataset and produce a comparable output with statistics on that fit. This is primarily for machine learning programs to compare their output against Kintecus' output. This validate feature should be used in conjunction with the mechanism validation feature to improve ML/DL models.
  • The NEW Jet Propulsion Laboratory multi-parameter fit the Troe expression for atmospheric, gas, combustion chemistry. Please see section 2 in the JPL Evaluation #19, 2019 ( For 2019, JPL has performed a complete revision on some of these fits.
  • The Kintecus Workbench has been expanded to include many more example models (some published), tools, examples, and other codes (such as Atropos). See "What's New" for a picture of the Kintecus Workbench Menu system!
  • Water Purification and Analysis files are constantly being added to the package. Please check the latest package distribution for the contents.
    (Package 3 is available for download as of Sept 2022)
  • More features! See What's New for more details!


Graphical Interface - Some screen shots and VIDEOS of the graphical interface for Kintecus.
Download - download Kintecus, pre-post processors, models or read the online documentation!
Testimonials - read what others think about Kintecus

Papers/Cites - view published refereed papers that use and cite Kintecus
and User submitted Kintecus material

- Frequently Asked Questions
Purchase- Register or Buy or Purchase Kintecus Licenses Here!
Atropos - Tired of large, slow, bulky chemical kinetic reaction systems? Tired of referees claiming your large chemical mechanism is superfluous and/or redundant? Try the new Kintecus software addition : Atropos !!


For Acolytes of Kintecus here is a small list of the program's features:

What Is Kintecus ????



The Kintecus chemical simulation software, chemical kinetics program, chemical kinetics software with full regression/optimization abilities and has been cited in over 400+ peer reviewed journals: SCIENCE, NATURE, J. Phys. Chem.A, PCCP, J. Biol. Chem., Plas. Chem. Plas. Proc., Int. J. Chem. React. Tech, Arch. Bio. Chem. Bio. Phys., etc.  Click the Papers button on the left side to see some! Kintecus is a powerful Industrial Strength/Research Grade chemical modeling software for simulation and optimization/regression of combustion, nuclear, biological, enzyme, atmospheric and many other chemical kinetic and equilibrium processes.

KINTECUS  - What can it do ?

Kintecus is a compiler to model and regress/fit/optimize the reactions of chemical, biological, nuclear and atmospheric chemical kinetic and equilibrium processes.

A quick overview of the main features:

  • Fit/Optimize/Regress rate constants, initial concentrations, Lindemann/Troe/SRI/LT parameters, enhanced third body factors, initial temperature, residence time, energy of activation and many other parameters against your dataset(s). Note that Kintecus will actually fit the parameters at EXACTLY the time your data was measured. Unlike other programs, Kintecus DOES NOT interpolate a function against your data and then fit the values against this interpolation. There is absolutely no need to “clean” your data, suggest interpolation methods nor specify timing meshes against your experimental data since Kintecus calculates values at exactly the times you specify in your experimental datafile. Kintecus V3.8 and above can also perform accurate bootstrapping of errors.

  • Global Data Regression/Fitting/Optimization Analysis: Kintecus V5.0 and up now supports an extremely powerful global data regression/fitting/analysis. You can regress or fit or optimize multiple datasets that have multiple initial conditions such as temperatures, pressures, concentrations or any combination and with data sets that have different time scales, different time steps, different species, temperature profiles, heat output, different amount of data points, etc. There are many sample Kintecus-Excel worksheets demonstrating some basics of this new global regression.

  •    Fitting/Regressing with Arbitrary Constraints/Conditions/Heat Output: Apply any type of constraints of any type of complexity in equation form
    between any variable or constants for use in regression/fitting.

  •   Local Variable Regression: One can now also regress/fit the initial conditions for a species (or temperature) in any of the initial_conditions.txt file (some programs call this local variable fitting/regression). This can be done by suffixing any numeric value in an initial condition file with a question mark, “?”. Kintecus V5.00 and up also supports the ability to regress/fit against heat generated during a reaction.

  • User Defined Chemical Rate Equations: The special USER chemical kinetic function is new in Kintecus V6.51. You can use it to define your own chemical kinetic rate equations of any complexity using ANY mathematical form.

  • Full output of global normalized sensitivity coefficients selectable at any specified time or times. Normalized sensitivity coefficients are used in accurate mechanism reduction, determining which reactions are the main sources and sinks (network analysis) and which also shows which reactions require accurate rate constants and which ones can have essentially guessed rate constants.  Kintecus V6.8 and up now include the Atropos system for full chemical mechanism elucidation and automatic reduction.

  • A very thorough and easy to use Uncertainty Analysis (Monte Carlo sampling runs) to calculate "real-life" averaged behaviors with confidence bands/standard deviations of your chemical system given Gaussian/Poisson/Uniform deviations.

  • The ability to use profiles or perturbations of any wave pattern for any species, temperature, volume or hv. Using profiles/perturbations can also be used for studying very realistic systems, such as quenching affects, dissolution of various gases into a system over time, induction of current into a system, heat flow into a system, a piston compressing the reaction chamber and so on.

  • Built in support for special reactions such as: reactions involving third-bodies (M), fall-off reactions (Troe, Lindemann, SRI, JPL forms, MCM forms, etc.) , enhanced third bodies, exclusive multiple enhanced third bodies, vibrational transfer reactions (Landau-Teller) and many others.

  • Some heterogeneous chemistry can be modeled. For example, a species in the aqueous phase will not contribute to the overall pressure in the system or be involved in third-body reactions or fall- off reactions. Gaseous species can “enter” other phases through out a simulation and vice-versa.

  • The ability to do reactions in a continuous stirred tank reactor or homogenized plug-flow reactors (CSTR,PFR) with multiple inlets and outlets and independent FLOW temperatures.

  • Kintecus V5.5 and up now support some of the special IUPAC chemical kinetics forms from the Master Chemical Mechanism (MCM) ( see , and/or or Google/Bing "Master Chemical Mechanism"). Most of the these forms pertain with special pressure fall-off reactions that cannot be fully cast into the traditional Troe, Lindemann forms.

  • The ability to convert Chemkin-II/Chemkin-III/Senkin models to Kintecus format. Kintecus can run almost any converted Chemkin model. Once converted, you may apply any Kintecus feature to the system. Do not be surprised to see the converted system run much faster! In addition, Kintecus can use multiple Chemkin thermodynamic databases at the same time and provides a way to use “reserve” species to a respective thermodynamic database. One can also convert the databases to a “freeform” format, which can be loaded into Excel. The “freeform” database is much easier to maintain and update. In addition, the converted model is not limited to several elements, in fact, your model can contain the entire Periodic Table.

  • Comes with multiple thermodynamic databases containing thermodynamic data (G,E,H,S,Cp,K,Kp) on several thousand species over a wide temperature range (200K-6000K)!

  • Reactions, adiabatic or non-adiabatic (isothermal, any temperature program), can be performed under isochoric (constant volume) or isobaric (constant pressure) with a simple flick of a switch along with optional volume, temperature, concentration wave perturbations or set profiles.

  • The ability to model thousands and thousands of reactions in a relatively short time. Kintecus has been used with models as large as 120,000+ chemical reactions. You will not find anything faster than Kintecus.

  •  Multiple-well, Multiple-channel Reactions Utilizing Chebyshev Polynomials and PLOG reactions. Kintecus V5.5 and up now support the Chebyshev expansions proposed by Venkatesh for representing pressure fall off and temperature dependant rates of multiple well reactions. Please see those references for the list of equations that are utilized in Kintecus to calculate those rates.

  • Global Equilibrium calculations. Why design a kinetic scheme when all you have to do is give Kintecus a listing of all the relevant species in your system. No need for ANY
    In fact, you do not even have to specify which species are reactions or products! You can even perform phase stability plots of systems over ranges of temperatures,
    pressures, volumes and concentrations of other species. You can even fit/optimize experimental data against your equilibrium model.
  • Users can utilize the OUTC[] operator for a species for reaction rates that involve families of species such as "ROH=[C2H5OH]+[C3H7OH]+[C4H9OH]+..."

  • The ability to compute all internal Jacobians analytically. This is very useful for simulating very large kinetic mechanisms (more than 50,000 chemical reactions). Finite difference methods can cause underflow or overflow errors in approximately such large Jacobians during the simulation.

  • Perform eigenvalue-eigenvector analysis of the Jacobians of the system as the model runs. This is useful for metabolic control analysis (stability analysis).
  • Easily perform four types of scanning: combinatorial, parallel, parallel-repeat and sequential.
  • A powerful parser with automatic mass & charge balance checker for those reactions that the graduate student "supposedly" entered in correctly but the model is yielding incorrect results or is divergent. Do you know a kinetics program that can completely parse and check for mass/charge balance on a reaction like this:

    Rate Constants , (m and Ea), REACTIONS:

    1.234e-20, 1.2, 3000,CH3(((NO2)3(CO)93)3 (CH2)9)+23.30H2O+ + Co2 ==> A--- + B++++ +C+C+C+C+C

    Or how about this:

    Rate Constants , REACTIONS:

    5.043e+20 , 3.43234 (CH4(N(PO342)43(CH3)3)34)(Os(S7)8)34++++ + 199.432 X++++ 5CH5+ ==>5.434 Some_Really_Funky_Long_Enzyme_Name+ 8 HCl + HCO3-

    This smart mass balance can be used for biological and nuclear reactions! Kintecus also provides duplicate reaction and species checking.

  • As you can see in the above reaction, fractional coefficients for species! Now you can finally model that last step in the Oregonator or crunch 100 elementary reaction steps in one reaction step!

  • Dynamic mode for feedback and/or dynamic simulation runs and external user control of Kintecus
  • Automatic generation of the species spreadsheet file using the reaction spreadsheet file. Why waste time finding, entering and initializing all the different species in your kinetic scheme?
  • The ability to perform complex hierarchical cluster analysis on temporal concentration profiles of the network with/without experimentally obtained temporal concentration profiles. Hierarchical cluster analysis in Kintecus has the ability to group related and unrelated parts of temporal concentration profiles in a meaningful, quantitative way. This grouping allows a user to clearly see patterns that were initially indiscernible or hidden.
  •  For accurate chemical mechanism determination, rate constant fitting and regression the application of all methods listed in Stanbury and Hoffman's 2019 paper "Systematic Application of the Principle of Detailed Balancing to Complex Homogeneous Chemical Reaction Mechanisms" will be included in Kintecus. Apparently, it appears that given a valid chemical mechanism, such a mechanism might be invalid even though the chemical mechanism may make “chemical sense”. Kintecus will be able to perform this analysis completely and automatically within itself simply by adding the "-MECHV" switch on the Kintecus command line! This should be used in conjunction with the mechanism validation feature to improve ML/DL models for 3D CFD runs.



This section is for people who do not read or even scan the main documentation. If you still cannot run your model after following the below short procedure then you should read the tutorial in the first section of the documentation.

  1. ) Go into command mode (on the Windows start button select RUN, type "command" and press the <ENTER> key ) and create a file named MODEL.DAT.
    - If you have Excel you can use the blank Kintecus_workbook.xls or Enzyme_Regression_Fitting.xls or GRI_MECH_30.xls and click the MODEL tab located at the bottom.

    However, if you don't have access to Excel, then use a text editor and enter your reactions like so:

    1.323e-4, A- + Widget-- + C==>G+++ + F---+H20
    3.2 , E+F ==> G + DNA_A_Replicated
    54.34 , G = A
    END ( <==-- Make sure this END is here)

    If you have Arrhenius expressions, then do your reactions like this (make sure you specify the correct Energy of Activation units in the parm.dat spreadsheet, look for the Ea Units field and type either Calories, Cal, Joules, J, KJ, KCAL or Kelvin:

    1.323e-4, -1.2, 3000, A- +Widget-- + C==>G+++ + F---+H20
    3.2 , 0.3, 2000, E+F == > G + DNA_A_Replicated
    54.34 , 2.1,5430, G = A
    END ( <==-- Make sure this END is here)
  2. ) Run Kintecus with the following switch: >Kintecus –c
    (If you are using EXCEL: click the "Make Species Worksheet from Model" button located on the CONTROL worksheet)
  3. ) Now copy the created ADDSPEC.TXT file as a SPECIES.DAT file (If you are using EXCEL: skip this step!)
  4. ) Edit the Initial concentration fields in species.dat for your model and type "Y" in the DISPLAY field for species' concentrations you want to save.
    (In EXCEL: click the species tab located near the bottom and then edit the same fields in the species worksheet)
  5. ) Run kintecus: >KINTECUS -ig:mass -show.
    (In EXCEL: click the CONTROL tab located near the bottom and then click the RUN button to start your model!)
  6. ) If you are using the EXCEL modules, on the CONTROL worksheet, click the Plot Results button to plot your results!
  7. ) OPTIONAL: If you wish to do include thermodynamics (temperature and reverse rate autocalculations), just use the –THERM switch on the command line.
  8. ) OPTIONAL: If you wish to do sensitivity analysis just use the –SENSIT:1 on the command line.
  9. ) OPTIONAL: You shouldn't trust your kinetic/thermodynamic simulations given the size of the errors associated with rate constants, thermodynamic data, TROE, SRI, third-body parameters, initial concentrations, etc., etc.
    Perform a full automated Uncertainty Analysis (Monte Carlo sampling) with the inclusion of the "-CONF" switch on the command line. If you are using the Kintecus-Excel interface, you will see confidence band plots along with maximum and minimum concentrations/temperature plots.
  10. ) OPTIONAL: If you wish to FIT or REGRESS or OPTIMIZE (maximize product or minimize expensive or harmful intermediates) experimental data to a model, then have your data in a text file named (or Excel Worksheet), FITDATA.TXT with Time(s) as the first column, first row. The species names should follow the Time(s) heading on the same row. Place your species/temperature data under the appropriate species column (if a species is missing data for a time point, place an "N" in the cell). Append a question mark, "?", to the end of any number you wish for Kintecus to regress/fit. Run Kintecus with –FIT:2:3:FITDATA.TXT. You can also try –FIT:1:3:FITDATA.TXT , -FIT:1:1:FITDATA.TXT and –FIT:2:1:FITDATA. Many sample Kintecus-Excel worksheets demonstrate this feature.

Questions or problems regarding this web site should be directed to jianni10[el atto] .
Copyright (c) 2024  James C. Ianni. All rights reserved. Kintecus is a registered trademark.