[molpro-user] About non-HF orbitals used in CCSD(T) calculation

Chen Hui chenh at yfaat.ch.huji.ac.il
Mon Dec 21 17:56:26 GMT 2009

Dear Molpro users,
I have two questions concerning the use of non-HF orbitals in CCSD(T) 
and CCSD(T)-F12 calculations.
The first question is if it is possible in MOLPRO2009 to use non-HF 
orbital (DFT orbital for example) in UCCSD(T) calculation,
since there are this kind of practices for transition metal containing 
systems. I know generally it is of no problem for coupled
cluster calculation to use non-HF orbital, but my question is if MOLPRO 
also permit this. In manual I fail to get information about this.

My second question is that if it is possible in MOLPRO2009  to use 
non-HF orbital in UCCSD(T)-F12 calculation. In manual, I noticed
a sentence read "The MP2-F12, CCSD-F12, and UCCSD-F12 methods must use 
conventional (non-density fitted) spin-restricted Hartree-Fock
reference functions (HF or RHF)." in part 30.1. Does this mean that only 
HF orbital could be used?

Thank you for your answer of my questions above.

Hui Chen

More information about the Molpro-user mailing list