[ase-users] dftb+

[ricardo santos]

Hi,

I am really new to ASE and would like to use it to make some simulations
using dftb+.
I tried to run a first simple code which is the following:

-----------------------------------------------------
import os
from ase.io.dftb import read_dftb
from ase import Atoms
from ase.calculators.dftb import Dftb
from ase.optimize import QuasiNewton
from ase.io import read
from ase.io import write
from ase.md.verlet import VelocityVerlet
from ase import units


atomos = read('H.xyz',index=0)
calc =
Dftb(label='dftb',write_dftb=True,include_dispersion=True,md_dftb=True\
       ,dftb_nsteps=3,md_restart_frequency=1,md_dftb_berendsen_nvt=True )
atomos.set_calculator(calc)
dyn = VelocityVerlet(atomos,dt=1.0*units.fs)
dyn.run(steps=10)
write('test.final.xyz', atomos)
-----------------------------------------------------

but got the error message:

Traceback (most recent call last):
  File "gas_ase.py", line 22, in <module>
    dyn.run(steps=10)
  File "/usr/lib/python2.7/dist-packages/ase/md/md.py", line 29, in run
    f = self.atoms.get_forces()
  File "/usr/lib/python2.7/dist-packages/ase/atoms.py", line 590, in
get_forces
    forces = self._calc.get_forces(self)
  File "/usr/lib/python2.7/dist-packages/ase/calculators/dftb.py", line
236, in get_forces
    self.update(atoms)
  File "/usr/lib/python2.7/dist-packages/ase/calculators/dftb.py", line
188, in update
    self.initialize(atoms)
  File "/usr/lib/python2.7/dist-packages/ase/calculators/dftb.py", line
228, in initialize
    self.write_dftb_input_file(atoms)
  File "/usr/lib/python2.7/dist-packages/ase/calculators/dftb.py", line
442, in write_dftb_input_file
    tmpvelocities = atoms.get_velocities().copy()
AttributeError: 'NoneType' object has no attribute 'copy'


Could someone help me to figure out what is the problem ?

Thank you in advance.


-- 
==================================================
Ricardo Paupitz B. dos Santos
Assistant Professor
*http://scholar.google.com/citations?user=BZBtHU4AAAAJ
<http://scholar.google.com/citations?user=BZBtHU4AAAAJ>*
CV: *http://lattes.cnpq.br/5313696806283523
<http://lattes.cnpq.br/5313696806283523>*

*Universidade Estadual Paulista - UNESP     *
IGCE - Instituto de Geociências e Ciências Exatas
Departamento de Física - Room 45
Av. 24-A n. 1515 Bela Vista
CEP 13506-900
Rio Claro (SP), Brasil
Phone: +55-19-3526 9156
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