Hello I have MO # 7 for F2
You will notice that pz orbitals coming from each F atom has a different sign. For this reason, this MO should be antibonding, Q-CHEM draws as bonding, what am I missing?
This is a question for a basic QM textbook. This forum is for help using and running the software. Basic chemistry questions are out of scope.
For a sigma MO, the opposite signs on the two p_z indicate a bonding orbital—the two p_z orbitals need to orient in opposite directions for their positive (or negative) lobes to overlap to form a sigma MO.