Nanotube in Abinit
To make a suitable
.in file from
the graphene sheet,
$ c2x -y=7,0 -v --abinit graphene.cell tube.in
ecut parameter was changed to "450 eV" and
prtvclmb 2 prtvha 1
appended to the file. A tube.files file was created containing
tube.in tube.out none tube tmp C.psp8
and a pseudopotenial supplied by gunzipping C.psp8.gz.
Then Abinit was run:
$ abinit < tube.files > tube.log
The run took about four minutes, mostly due to the use of a rather unoptimised build of Abinit.
The potential far from the tube (i.e. at (0,0,0)) and at the centre of the tube (i.e. at (0.5,0.5,0.5)) can then be recovered as:
$ c2x -z='(0,0,0)' tube_VCLMB Potential_VCLMB at (0.000000,0.000000,0.000000): 3.927966e+00 $ c2x -z='(0.5,0.5,0.5)' tube_VCLMB Potential_VCLMB at (0.500000,0.500000,0.500000): 3.169207e+00
So a potential difference of about 0.759V. One can also ask c2x to calculate the potential from the charge density:
$ c2x -E -z='(0,0,0)' tube_DEN Potential_Volts at (0.000000,0.000000,0.000000): -3.941573e+00 $ /c2x -E -z='(0.5,0.5,0.5)' tube_DEN Potential_Volts at (0.500000,0.500000,0.500000): -3.187123e+00
Now a difference of 0.754V.