The optimization of the molecule in all trans and all cis have been done. Now, how to calculate the isomerization energy from the DFT Calculation?
Hello Parna,
The energy of isomerization should be the difference in energy between them. Also, if you want to calculate enthalpies... and other factors you must run a freq calculation too.
On the other hand, locate the TS of the isomerization can help with all parameters of the reaction or draw the potential energy of isomerization (very common and useful but depending on the system).
I hope it helps you
Joaquim is right. I would additionally recommend to perform a (relaxed) scan or NEB calculation to observe the isomerization process.
thank you .
I would like to do the calculation for iridium complexes and I really do not know much regarding the calculation.
I can see that optmization and frequency can be calculated together. what are the parameters needed for the calculation to get the enthapies.
secondly how to perform NEB calculation? Can I run the calculation in DFT 09.
Hello Parna,
In the output there are "Thermochemistry (search it in document)" results where there are the Gibbs and enthalpy energies (including the electronic energy).
About the Iridium complex take a lot of care if you use a DFT method because it is very possible to obtain very bad results. Also think that in Ir the relativistic effect can imply an important role. I think that find a good method and basis set with relativistic effects included should be important for this kind of systems. (See any review or book about Problems with DFT methods).
If it is an iridium complex you might check for relativistic effects and multi-configuration character in the system.
My PhD thesis was all about calculating the cis-trans azobenzene derivitaves isomersation energy, you can have a look at it may be it is useful!
I would really doubt that rotation around double bond can be well described by single-reference method.
- Badges
- Science topic
- Similar topics
- Engineering
- Chemical Engineering