51 lines
1.8 KiB
ReStructuredText
51 lines
1.8 KiB
ReStructuredText
======
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casscf
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======
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|CASSCF| program with the CIPSI algorithm.
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Example of inputs for GROUND STATE calculations
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-----------------------------------------------
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NOTICE :: FOR EXCITED STATES CALCULATIONS SEE THE FILE "example_casscf_multistate.sh"
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a) Small active space : standard CASSCF
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---------------------------------------
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Let's do O2 (triplet) in aug-cc-pvdz with the following geometry (xyz format, Bohr units)
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2
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O 0.0000000000 0.0000000000 -1.1408000000
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O 0.0000000000 0.0000000000 1.1408000000
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# Create the ezfio folder
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qp create_ezfio -b aug-cc-pvdz O2.xyz -m 3 -a -o O2_avdz
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# Start with an ROHF guess
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qp run scf | tee ${EZFIO_FILE}.rohf.out
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# Get the ROHF energy for check
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qp get hartree_fock energy # should be -149.4684509
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# Define the full valence active space: the two 1s are doubly occupied, the other 8 valence orbitals are active
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# CASSCF(12e,10orb)
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qp set_mo_class -c "[1-2]" -a "[3-10]" -v "[11-46]"
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# Specify that you want an near exact CASSCF, i.e. the CIPSI selection will stop at pt2_max = 10^-10
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qp set casscf_cipsi small_active_space True
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# RUN THE CASSCF
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qp run casscf | tee ${EZFIO_FILE}.casscf.out
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# you should find around -149.7243542
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b) Large active space : Exploit the selected CI in the active space
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-------------------------------------------------------------------
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#Let us start from the small active space calculation orbitals and add another 10 virtuals: CASSCF(12e,20orb)
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qp set_mo_class -c "[1-2]" -a "[3-20]" -v "[21-46]"
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# As this active space is larger, you unset the small_active_space feature
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qp set casscf_cipsi small_active_space False
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# As it is a large active space, the energy convergence thereshold is set to be 0.0001
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qp run casscf | tee ${EZFIO_FILE}.casscf_large.out
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# you should find around -149.9046
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