I am trying to calculate the spin-orbit coupling value for cyclobutadine. Here is my input.
# casscf=(2,2,spinorbit)/3-21g
But it is stopping at
Enter MCSCF program.
NO. OF ORBITALS = 44 NO. OF CORE-ORBITALS = 13
NO. OF VALENCE-ORBITALS = 2 NO. OF VIRTUAL-ORBITALS = 29
USED ACCURACY IN CHECKING CONVERGENCE = 1.00D-08
I am not sure what exactly the issue is? I think i am missing something in the input. Kindly help me out.