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Re^4: Starting virtual orbitals for MCSCF

Pavlo Solntsev
pavlo.solntsev@gmail.com


Alex,

Thank you for comments and the link. At least i know which orbitals i should use and how to get them. One more question. I played with benzene as a test and realized that ChemCraft can't read NBO orbitals for point group .gt. C1. Should i use just another viewer or i can re-read NBO orbitals with prtmo=.t. and runtyp=prop and visualize them.

Pavel.



On Thu Mar 13 '14 11:38pm, Alex Granovsky wrote
-----------------------------------------------
>Pavel,

>>I got a NBO license. May i ask you some questions about this module.
>>I did SP calculation using $nbo file=.... plot $end line. I got NBO's files. NBO orbitals in the PUNCH file corresponds to the NBO orbital from *.37 file, do they? Is it enough to use NBO orbitals as initial orbitals for MCSCF or should I also look into different NBO files?

>I'd suggest to visualize NBOs using ChemCraft and select active space.

>Then add

>

 $nbo aonbo $end 

>to the input and you'll get NBOs in the punch file as well:

>

NBOs in the AO basis:                                                           
 $VEC....

>
>
>
>>Is there any trick i should know for non-singlet systems? I saw, beta and alpha orbitals are different.

>I can only recommend to inspect both sets.

>Also, check papers containing "CAS/NBO" keyword. The base paper is:

>http://scitation.aip.org/content/aip/journal/jcp/97/2/10.1063/1.463289http://scitation.aip.org/content/aip/journal/jcp/97/2/10.1063/1.463289

>Kind regards,
>Alex
>
>
>
>
>
>>Any comments maybe not form you, but from any user of NBO code in FF will be useful.

>>Pavel.
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>>On Thu Mar 6 '14 6:51pm, Alex Granovsky wrote
>>---------------------------------------------
>>>Hi,

>>>if you have NBO license you can try to visualize and use NBOs.

>>>Kind regards,
>>>Alex Granovsky
>>>
>>>
>>>
>>>On Thu Mar 6 '14 6:38pm, Pavlo Solntsev wrote
>>>---------------------------------------------
>>>>Hi,

>>>>Maybe somebody had this problem before. I am working on a system with two copper centers. THis system was found to be multireference in nature. I have already done some calculations and solution looks good that makes me happy. However, i need to expand my active space. I need to include some 3d-orbitals from coppers (they were not included before) and corresponding 3d' virtual orbitals to keep active space balanced. I started from CIS-NO. All 3d orbitals may be found easily. However, situation with virtual orbitals is not so simple. I may see some virtual orbitals of d-character but very delocalized over coppers and ligands. I also checked VVOs orbitals from GAMESS-US but it doesn't solve the problem. The worst thing is i need to include not all 3d orbitals but only xz,yz and z2 (square-planar copper(II)). How can i purify my virtual orbitals to make them more localized?

>>>>Thank you for any help.
>>>>Pavel.
>>>>


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