Fractional occupied orbitals

Matt W MattWa... at gmail.com
Thu Oct 1 22:29:51 CEST 2015


Hi Natalie,

the warning is just for the calculation of the S**2 operator - i.e the 
expectation value of the total spin for the system. The value of it for DFT 
is a bit uncertain anyway...

The spin density is a totally different thing, and should be fine to use in 
analysis. Same goes for all properties that can be output as cube files I 
can think of.

Matt

On Wednesday, September 30, 2015 at 4:13:43 PM UTC+1, Natalie Austin wrote:
>
> Hello,
>
> I have a system consisting of Cu55
> In this section I've included smearing and added mos: 
>
>   &SCF
>      SCF_GUESS  ATOMIC
>      EPS_SCF 1.0E-6
>      MAX_SCF 500
>      ADDED_MOS  200
>      CHOLESKY INVERSE
>      &SMEAR  ON
>          METHOD FERMI_DIRAC
>          ELECTRONIC_TEMPERATURE [K] 300
>      &END SMEAR
>      &DIAGONALIZATION
>           ALGORITHM STANDARD
>      &END DIAGONALIZATION
>      &MIXING
>           METHOD BROYDEN_MIXING
>           ALPHA   0.1
>           BETA    1.5
>           NBROYDEN  8
>      &END MIXING
>  &END SCF
> UKS .TRUE.
>
>
> At the end of my output file I get the warning: 
>
>   Integrated absolute spin density  :                               
> 0.0003914226
>   WARNING: S**2 computation does not yet treat fractional occupied orbitals
>
> Is this warning relevant to just the spin density of does it have an 
> effect on the total energy? 
> If this means the spin density is unrealible, how would I go about in my 
> analysis of total density,homo-lumo gap. Basically, if I were to generate 
> cube files based on this calculation would they be accurate?
>
>
> Thanks,
>
> Natalie
>
>
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