I'm doing a part-time calculation using Gaussian DFT method. My molecules contain C, H, N, P and Pt (Au/Ru sometime). I read some papers, they use split basis set for this kind of molecule, and very often they use LANL2DZ for Pt and 6-31G* for C, H, N and P.
So i have 2 questions regarding this matter, please help me!
1- How important it is to use split basis set? Regardless of computational time, the split basis set LANL2DZ + 6-31G* vs LANL2DZ ONLY to all atoms, which calculation should offer a better result?
2- How to include the basis set to the .com input file? Let's take an example below.
----- .com input file------------
%nprocshared=8
%mem=8GB
%chk=cisa.chk
# opt B3LYP/GEN pseudo=read geom=connectivity
Cisa
0 1
Pt -0.98014889 -1.12903224 0.00000000
O -0.98014889 0.82096776 0.00000000
H -0.98032420 1.14142234 0.90493581
O -2.93014889 -1.12903224 0.00000000
H -3.25060347 -2.03241238 -0.05303937
H 0.02861950 -3.54569859 0.00868705
H -1.49205651 -3.54569859 0.86927539
H -1.47700967 -3.54569910 -0.87796248
H 1.43651746 -1.50543668 0.93595343
H 1.43651746 -1.75138926 -0.79395268
H 1.43651797 -0.13027074 -0.14200076
N 1.07985111 -1.12903224 0.00000000
N -0.98014889 -3.18903224 0.00000000
1 2 1.0 4 1.0 12 1.0 13 1.0
2 3 1.0
3
4 5 1.0
5
6 13 1.0
7 13 1.0
8 13 1.0
9 12 1.0
10 12 1.0
11 12 1.0
12
13