Tips for Microkinetic Modeling: Difference between revisions
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go back to [[Main Page]], [[Group Pages]], [ | go back to [[Main Page]], [[Group Pages]], [[Feliu Maseras and Group]] | ||
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Tips: | Tips: | ||
* You | '''* You cannot do "never ever" trimolecular reactions'''. | ||
If you have a reaction like A + B + CAT -> D. You will have to split it in two reactions ( i.e. A + CAT -> ACAT and ACAT+B -> D or similar). | |||
If you tray to do trimolecular reactions you will get different answers depending on the program you are using. Acuchem will stop giving and error and Copasi will create a stupid new variable called B+CAT. | If you tray to do trimolecular reactions you will get different answers depending on the program you are using. Acuchem will stop giving and error and Copasi will create a stupid new variable called B+CAT. | ||
* You might encounter negative concentrations | '''* You might encounter negative concentrations of starting materials''' (Ángel and Mauro found it in Tenua and Copasi). | ||
Don't get mad if you have this problem. Maybe you got wrong at the description of your system or maybe you're having a mathematical error during the resolution of the differential equations. A way to avoid it consists on modifying the relative and absolute tolerance during the integration (10-13 and 10-16, respectively). The smallest the better. Ángel and Mauro found that the modification of these parameters are fundamental to have reliable results. Copasi has a value of 10-6 as default. | |||
Latest revision as of 09:43, 25 October 2018
go back to Main Page, Group Pages, Feliu Maseras and Group
Please have a look at "Besora M., Maseras F.. Microkinetic modeling in homogeneous catalysis. WIREs Comput Mol Sci 2018, 8, doi: 10.1002/wcms.1372 File:Wcms.1372.pdf
Programs:
- Tenua (very bad don't use it)
- AchuChem: reliable and simple but not many options available.
- Copasi: reliable and with lots of options
Tips:
* You cannot do "never ever" trimolecular reactions.
If you have a reaction like A + B + CAT -> D. You will have to split it in two reactions ( i.e. A + CAT -> ACAT and ACAT+B -> D or similar). If you tray to do trimolecular reactions you will get different answers depending on the program you are using. Acuchem will stop giving and error and Copasi will create a stupid new variable called B+CAT.
* You might encounter negative concentrations of starting materials (Ángel and Mauro found it in Tenua and Copasi).
Don't get mad if you have this problem. Maybe you got wrong at the description of your system or maybe you're having a mathematical error during the resolution of the differential equations. A way to avoid it consists on modifying the relative and absolute tolerance during the integration (10-13 and 10-16, respectively). The smallest the better. Ángel and Mauro found that the modification of these parameters are fundamental to have reliable results. Copasi has a value of 10-6 as default.