I am using Gaussian 16 to optimize a paraquat molecule on top of a bulk of gold atoms. Some of these gold atoms are frozen, so I use the option
opt=modredundant. I also want to use different basis sets for the calculation of different atoms. I found the option of using
gen. My root section is as follows:
#p opt=modredundant b3lyp/gen nosymm int=ultrafine
After the root section, I specify the title, charge, and multiplicity. The
.gjf file includes the coordinates for the atoms and the information on which atoms should be frozen (e.g.
X 54 F).
Do I put the code to specify the basis sets after the coordinates, after the frozen atoms, or at the very end of the
H C N 0
Thank you for your answers!