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Re^4: Problem with SOC (spin-orbit coupling) calculations

Maksim Shundalau

Alex, thank you very much!


On Sun Jan 17 '16 7:04pm, Alex Granovsky wrote
>Dear Maksim,

>The problem you encountered is caused by invalid transt, cidrt1
>and cidrt2 groups. For your computations these groups should be
>as follows:


 $cidrt1 fors=.true. nfzc=8 ndoc=0 nval=9 next=0 naos=1 nbos=1 nalp=1 $end

 $cidrt2 fors=.true. nfzc=8 ndoc=0 nval=9 next=0 naos=0 nbos=0 nalp=3 $end

  numci=2 numvec=1 nfzc=8 nocc=20 iroots(1)=11,11

>Some additional comments:

>1. Do not use coord=zmt or zmtmpc for runs exporting/importing orbitals,
>as molecule could be rotated differently as in the preceding run.
>Use coord=unique instead. In addition, you may need to recompute
>orbitals from the scratch.

>2. Use $contrl wide=.t. $end throughout to export/import orbitals.

>Kind regards,
>Alex Granovsky
>On Fri Jan 15 '16 11:58am, Maksim Shundalau wrote
>>Dear Alex!

>>Firstly I calculated terms of the YbCs molecule at the SA-CASSCF level of theory from asymptotical limit (20 A) to the shot distance (3 A) point-by-point with step 0.05 A. I get 3 valence electrons and 12 orbitals for active space, and 14 states (11 doublets and 3 quartets) in SA procedure. I use Stuttgart ECP basis sets. I perform single-point calculation at a certain point, and then I take optimized vectors from PUNCH and perform single-point calculation at a next point, etc. Also I’m watching the states in SA.
>>In result I have smooth PECs for the ground and some excited states of YbCs.
>>For example, for the ground state PEC I have:

>>7.65 A CAS=-52.5164130391
>>7.70 A CAS=-52.5163908210
>>7.75 A CAS=-52.5163695661
>>7.80 A CAS=-52.5163495738

>>Secondly I calculated the terms at the XMCQDPT2 level of theory, and again I have smooth PECs. The details of the XMCQDPT2 calculations I can also describe, but the SOC calculations are performed on the CAS-vectors.

>>At least I calculated SOC with optimized CAS-vectors, and I have a problem. I get “breaks” in PECs, for example:

>>7.65 A CAS+SOC=-52.5164465294
>>7.70 A CAS+SOC=-52.5164233281
>>deltaE=0.00000115 !!!!!!!!!!!!!!!!!!
>>7.75 A CAS+SOC=-52.5164221806
>>7.80 A CAS+SOC=-52.5163986729
>>Thank you very much,
>>With best regards,
>>Maksim Shundalau.
>>On Thu Jan 14 '16 4:16pm, Alex Granovsky wrote
>>>Dear Maksim,

>>>could you please describe in details your computational protocol?

>>>Kind regards,
>>>Alex Granovsky
>>>On Tue Jan 12 '16 12:16pm, Maksim Shundalau wrote
>>>>Dear Alex!

>>>>I’ m trying to calculate PECs of the YbCs molecule at the CAS(3,12)/XMCQDPT2 + SOC (spin-orbit coupling) level of theory with Stuttgart ECP basis sets.
>>>>I have smooth terms at the CAS(3,12) and at the XMCQDPT2 levels of theory. But I have “breaks” in PECs, when I’m calculating SOC (see, for example, figs.pdf).

>>>>What’s the problem here?

>>>>Thank you very much,
>>>>With best regards,
>>>>Maksim Shundalau.

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