Things are more clear to me when I look at the basis set in CFOUR format, because of the information at the top which tells me how many primitives and how many contractionscontractions there are for each type of orbital:
O:MIDI
Huzinaga MIDI
2
0 1
3 2
6 3
281.86658 42.416000 9.0956200 11.46603 0.887860 0.278800
0.069060 0.000000 0.00000000
0.393159 0.000000 0.00000000
0.665669 0.000000 0.00000000
0.000000 -0.080820 0.00000000
0.000000 0.582090 0.00000000
0.000000 0.000000 1.00000000
8.047240 1.668420 0.372510
0.124271 0.00000000
0.476594 0.00000000
0.000000 1.00000000
I'm going to use the % symbol to add comments on the numbers at the top, to explain what they mean (but adding comments like this won't work if you actually did this to your GENBAS file in CFOUR):
2 % # of types of orbitals = 2 (S and P).
0 1 % 0 = S, 1 = P, 2 = D, 3 = F, etc.
3 2 % 3 contractions for S, 2 contractions for Px, 2 for Py, 2 for Pz
6 3 % 6 primitives for S, 3 primitives for Px, 3 for Py, 3 for Pz
This explains why the basis set in GAMESS(US) format is showing 6 primitives for S and 3 primitives for P, but in your final eigenvectors, we now consider the contractions:
- 3 for S
- 2 for Px
- 2 for Py
- 2 for Pz
This is exactly what your output shows!