I am performing ab initio calculations on a heteronuclear diatomic compound using the MRCI method on the MOLPRO quantum chemistry package. I obtained the molecular states of the compound but I was wondering how to find the molecular orbital configuration of each electronic state in addition to their associated compositions. I tried to include the "print, orbitals" before and after the CI, but I didn't get anything! Your help and support are much appreciated...

  • $\begingroup$ MRCI does not optimize the molecular orbitals. They remain in whatever you used as input orbitals for MRCI (typically from a preceding CASSCF calculation). $\endgroup$ – Feodoran Oct 8 '19 at 10:31
  • $\begingroup$ I used HF and MCSCF before the CI calculations. Are they generated in the HF or in the MCSCF? $\endgroup$ – Naps Oct 8 '19 at 12:52
  • $\begingroup$ both methods generate orbitals. but what you are interested in are the MCSCF orbitals (assuming your calculation input is set up appropriately). CASSCF is just a special case of MCSCF. $\endgroup$ – Feodoran Oct 8 '19 at 22:35