Multiwfn forum

aitouna

Member

Registered: 2019-10-27

Posts: 20

Urgent Question

Hello everybody in the forum
It is necessary to use the keyword integral=ultrafine when we use the Minnesota density functional M06-2X in the optimization process ?
Should i repeat all the calculations ?

Note: I forget to use the keyword, and the optimization converged.

sobereva

Tian Lu (Multiwfn developer)

From: Beijing

Registered: 2017-09-11

Posts: 1,830

Website

Re: Urgent Question

Dear aitouna,

If you are using G16, the "int=ultrafine" is default keyword, you do not need to manually specify it.
If you are using G09, the difference in the geometries optimized using "int=fine" and "int=ultrafine" is usually negligible and thus you do not need to repeat all calculations. However, if the studied system is weakly bounded complex or the structure is quite flexible, it is best to make all optimizations conducted at the same quality of integral grid.

Tian

aitouna

Member

Registered: 2019-10-27

Posts: 20

Re: Urgent Question

Dear Professor Tian LU,

Thank you very much for your help.

Sincerely,