I am an ORCA User,
Thank you for guiding me through the following question;
Is there any difference in the calculated energies resulted from ORCA and other softwares like Gaussian, GAMESS and so on?
What is the ORCA advantage over others in this respect?
Very thank you
Energies should be equal IF the same functional and integration grids are used. Default integration grids for a few packages are :
- Gamess (US) : uses a Lebedev grid with 96 radial points per atom and 302 angular points per radial shell
- Firefly : a pruned Lebedev grid with 63 radial points per atom and 302 angular points per radial shell
- Q-Chem: the "standard grid-1" , which is a pruned version of a Lebedev grid with 50 radial points per atom and 194 angular points per radial shell.
- Orca: a pruned Lebedev grid with a variable number of radial points per atom ( 30 for 1st row, 55 for 2nd row, 40 for 3rd row elements, etc.) and 302 angular points per radial shell.
- Gaussian09 : a pruned Lebedev grid with 99 radial points per atom and 590 angular points per radial shell
Dear Farshad Shiri ,
I think that it depends on which energies you are talking about. If you are talking about total energies, then the calculated energies are likely different. If you use the same exact basis set and effective core potentials, then it's possible that your calculated total energies from different codes will be similar. However, it is generally not advisable to compare total energies across different codes. If you are talking about energy differences (e.g. formation energies, binding energies, etc.), then, as long as you are using good effective core potentials and a sufficient basis set, these codes should give similar results. I hope that this was helpful, please let me know if you have any further questions.
Best,
Rob
Energies should be equal IF the same functional and integration grids are used. Default integration grids for a few packages are :
- Gamess (US) : uses a Lebedev grid with 96 radial points per atom and 302 angular points per radial shell
- Firefly : a pruned Lebedev grid with 63 radial points per atom and 302 angular points per radial shell
- Q-Chem: the "standard grid-1" , which is a pruned version of a Lebedev grid with 50 radial points per atom and 194 angular points per radial shell.
- Orca: a pruned Lebedev grid with a variable number of radial points per atom ( 30 for 1st row, 55 for 2nd row, 40 for 3rd row elements, etc.) and 302 angular points per radial shell.
- Gaussian09 : a pruned Lebedev grid with 99 radial points per atom and 590 angular points per radial shell
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