# Fixing occupation numbers

Michael Trumm trummm... at gmail.com
Thu Aug 4 12:46:37 UTC 2016

```Ahoi,

i am trying to perform some atomistic calculations using fractional
occupation numbers. (in this example it would be the neutral oxygen atom)
after i initialized them via &SMEAR the occupation looks kind of ok, but
during the run cp2k chooses one of the tripletts.
hence my question. is there any way to fix the fractional occupation during
the whole run to get a fractional triplett with the
beta p-orbitals occupied p_x 1/3  p_y 1/3 and p_z 1/3 ?

thanks for any help,
Michael.

OUTPUT:

ALPHA MO EIGENVALUES AND MO OCCUPATION NUMBERS AFTER SCF STEP 20

# MO index          MO eigenvalue [a.u.]            MO occupation
1                     -0.917069                 1.000000
2                     -0.394950                 1.000000
3                     -0.394539                 1.000000
4                     -0.312729                 1.000000
5                      0.468611                 0.000000
6                      0.493158                 0.000000
# Sum                                                     4.000000

Fermi energy:                -0.241121

HOMO-LUMO gap:                0.781340 =  21.26 eV

BETA MO EIGENVALUES AND MO OCCUPATION NUMBERS AFTER SCF STEP 20

# MO index          MO eigenvalue [a.u.]            MO occupation
1                     -0.778066                 1.000000
2                     -0.268824                 1.000000
3                     -0.213094                 0.000000
4                     -0.211852                 0.000000
# Sum                                                     2.000000

INPUT:

&GLOBAL
PROJECT test
RUN_TYPE ENERGY
&END GLOBAL

&FORCE_EVAL
METHOD QS
&DFT
LSD
MULTIPLICITY 3
&PRINT
&MO
OCCUPATION_NUMBERS
&END MO
&END PRINT
BASIS_SET_FILE_NAME BASIS_MOLOPT
POTENTIAL_FILE_NAME GTH_POTENTIALS
CHARGE  0
&SCF
&SMEAR
LIST 1-3 1/3
&END SMEAR
EPS_SCF 2.0E-5
&END SCF
&XC
&XC_FUNCTIONAL PBE
&END XC_FUNCTIONAL
&END XC
&END DFT
&SUBSYS
&CELL
ABC 5.189 8.953 20.129
ALPHA_BETA_GAMMA 90 101.11 90
PERIODIC XYZ
&END CELL
&KIND O
BASIS_SET DZVP-MOLOPT-GTH
POTENTIAL GTH-PBE-q6
&END KIND
&COORD
O        -0.9968591421        2.9869391388        4.8752526707
&END COORD
&END SUBSYS
&END FORCE_EVAL

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