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Re: FATAL ERROR: AUFBAU PRINCIPLE VIOLATION DETECTED for TDDFT

Alex Granovsky
gran@classic.chem.msu.su


Pavlo,

this error means that the reference (i.e. HF or DFT) state violates
the aufbau principle. In this context, aufbau principle states that
the energy of HOMO should be less than the energy of LUMO. TDDFT and
TDHF computations are only meaningful when aufbau principle is held.

As a workaround, try to find an alternative SCF solution. E.g. you
can swap HOMO and LUMO and try to converge SCF again. Nonetheless,
even with alternative SCF solution one typically can expect small
HOMO-LUMO gap and very low TDDFT excitation energy. It could be
helpful to perform MCSCF to check wf. for multireference character

All the best,
Alex


On Tue Nov 11 '14 7:51pm, Pavlo Solntsev wrote
----------------------------------------------
>Alex,

>By doing a TDDFT for a system i found this error. SCF minimization was finished successfully, but the error occurs at TDDFT stage. Could you please advise me how to solve this problem? I saw, AUFBAU principle was mentioned in CI section of the manual, but no word was said about this principle for TDDFT case. My input file:

> $CONTRL SCFTYP=RHF MAXIT=200 ICHARG=1 MULT=1 NZVAR=1
> inttyp=hondo icut=11 itol=30 dfttyp=pbe96 cityp=tddft $END
> $BASIS GBASIS=n31 ngauss=6 ndfunc=1 npfunc=1  $END
> $tddft nstate=5 istsym=1 mult=1 $end
> $dft nrad=99 lmax=41 $end
> $SCF DIRSCF=.TRUE. $END
> $DATA
>Cn 2

>.....
> $end

>I use Firefly version 8.1.0, build number 9035 .

>Thank you.

>-Pavlo.


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