Single point energy at different level

aitouna

Hello everybody,
A lot of articles used a different methods and basis sets for geometry optimization and single point energy calculations for the same molecules, I wonder if it's proper to get single point energies like this, and if it's yes, i would like to know what's the reason.


Sincerely,

sobereva

This is a very common treatment. Because geometry optimization is not as sensitive as single point energy to calculation level, using relatively cheap level to optimize geometry while employing better level to conduct single point is the most cost-effective computational protocol.

I wrote a blog post that is closely related to this topic, see http://sobereva.com/387 (despite that it was written in Chinese, you can easily understand why using inexpensive level for optimization is fully acceptable based on the table and figure).

aitouna

Thank you very much Professor.


Sincerely,