SCM: Examples

Cu₄CO: Density of States

Sample directory: adf/DOS_Cu4CO/

This sample illustrates the DOS property program to compute density-of-states data, for energy-dependent analysis.

First, the Cu₄CO molecule is calculated (ADF), using single-atom fragments.

$ADFBIN/adf <<eor
title  Cu4CO (3,1) from atoms

units
length bohr
end

define
rCu=2.784
end

atoms
1. Cu     rCu      0.0              0.0
2. Cu    -rCu/2    rCu*sqrt(3)/2    0.0
3. Cu    -rCu/2   -rCu*sqrt(3)/2    0.0
4. Cu     0.0      0.0             -rCu*sqrt(2)
5. C      0.0      0.0              2.65
6. O      0.0      0.0              4.91
end

Basis
  Type TZP
  Core small
end

XC
  GGA  PostSCF    Becke Perdew
END

endinput
eor

The PostSCF feature in the specification of the XC functional is used: the 'Becke-Perdew' GGA corrections are not included self-consistently but applied to the energy evaluation after the self-consistent LDA solution has been obtained.

The utility program dos requires a file named TAPE21 in the current directory, unless overridden using a TAPE21 keyword (not used in this example).

$ADFBIN/dos << eor
file dostxt

energyrange npoint=36 e-start=-25 e-end=10

tdos
 
! Cu 3d partial DOS
gpdos
  a1   14:22 32:34
  a2    5:10
  e1:1 18:32 37:42
  e1:2 18:32 37:42
end

! The same but using BAS 
gpdos
  BAS 17:34 57:74 97:114 137:154
end

! The same as above, but using much less complicated input
gpdos
  ATYPE Cu d
end

! Overlap PDOS between Cu 3d and CO 2p
opdos
  ATYPE Cu 3d
SUBEND
  ATOM 5 2p
  ATOM 6 2p
end

end input
eor

Here, the total density of states, as well as various partial densities of states, are computed. You may feed the results found in the dostxt file into a plotting program such as gnuplot. The result is not displayed here. See the Utilities document for more detailed info about the dos program.