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Re^2: How to localize Orbital

Alex Granovsky
gran@classic.chem.msu.su


Hi,

most likely you do not need localized orbitals at all...
I'm afraid they will mix up coefficients of CI expansion
rather than sum up to the single leading term.

What I'd suggest is to look at CI expansion based on natural orbitals.
You can find them in the punch file - just provide them
using guess=moread and run CI or MCSCF. Note you do not
actually need to converge MCSCF from the scratch - it will  
converge in a couple of iterations as NOs are already optimized.

By the way, NOs themselves tend to be rather local in the space -
you may want to look at them using e.g. ChemCraft. To some extent,
transformation to NOs can be considered as a kind of orbital localization procedure. It also tends to make CI expansion more compact.

Hope this helps.

Regards,
Alex Granovsky





On Thu Mar 11 '10 6:46pm, Neeraj Kumar wrote
--------------------------------------------
>Can anybody help me.For localization of orbital in MCSCF
>convergence....
>appreciate your help advance.
>
>
>
>
>On Thu Mar 11 '10 0:24am, Neeraj Kumar wrote
>--------------------------------------------
>>Hello
>>    i am new to firefly, I have converged (10,11) active space for my
>>model(having 45 atom) using MCSCF.And My system is closed shell and it
>>has C1 sym. My overall wave-function has complicated form because it
>>is multi reference. Now i came to now that this wave-function
>>substantially simplified by a transformation to localized
>>orbitals( because this operation does not effect the the overall wave-
>>function).My model has total 113 occupied orbital. So my wavefunction
>>has contribution from following major term {113(HOMO) and 114(LUMO)}.
>> 0.555943 (22222000000) + 0.380879 (22221100000) -0.250496
>>(22220200000)
>>So instead of three term, i wana single dominant term with more weight
>>in the total wave function
>>What I dont know how to use $Local and moreover its unclear from
>>manual. If any body has experienced with transformation to localized
>>orbital, Please help me. Could you please suggest me the command line
>>or if you have any input file please send me.
>>Here is the input for my system which is converged by  MCSCF.
>> $CONTRL SCFTYP=MCSCF RUNTYP=ENERGY MAXIT=200
>>  MULT=1 ICHARG=0 d5=1 EXETYP=RUN
>>  FSTINT=.TRUE. GENCON=.TRUE. $END
>> $SYSTEM TIMLIM=100000000000 MWORDS=300 NOJAC=100
>>  KDIAG=0 MKLNP=2 $END
>> $D5 d5=.TRUE. f7=.TRUE. $END
>> $GUESS GUESS=MOREAD NORB=487 $END
>> $SCF DIRSCF=.TRUE. DIIS=.TRUE. $END
>> $GUGEM PACK2=.TRUE. FASTCI=.TRUE. $END
>> $CIINP CASTRF=.TRUE. $END
>> $TRANS MPTRAN=2 DIRTRF=.T. AOINTS=DIST ALTPAR=.T. MODE=112 $END
>> $DRT GROUP=C1
>>      FORS=.TRUE.
>>      NMCC=108
>>      NDOC=5
>>      NVAL=6
>> $END
>> $GUGDIA NSTATE=1 ITERMX=100 $END
>> $MCSCF CISTEP=GUGA MAXIT=50 $END
>> $DATA


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