[ase-users] another nearest neighbor list question

[John Kitchin]

That doesn't make sense to me. There are 12 atoms that are equidistant
from the origin. The halflist shouldn't apply or change the results of
this case because there is only one atom in the unit cell.

If I make a 3x3x3 bulk fcc cell,  and get the neighbor list of the
central atom, then it returns only 8 atoms even with bothways=True. I
would have expected 12 atoms.

John

-----------------------------------
John Kitchin
Assistant Professor
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803
http://kitchingroup.cheme.cmu.edu





On Thu, Feb 17, 2011 at 9:49 AM, Tao Jiang <tjiang at fysik.dtu.dk> wrote:
> I think this is the half list as Jakob mentioned before. By doing so,
> the calculator such as emt does not need to go through the whole
> list twice to calculate the total energy.
>
> /TJ
>
>
> On Feb 17, 2011, at 3:25 PM, John Kitchin wrote:
>
>> for the nearest neighbor list, would you expect to get 12 results for
>> the atom at the origin of an FCC bulk lattice (not counting the atom
>> itself)? I only get 6 neighbors. Am I misunderstanding the results, or
>> how to setup the list?
>>
>> from ase.lattice.cubic import FaceCenteredCubic
>> from ase.calculators.neighborlist import *
>>
>> atoms = FaceCenteredCubic(directions=[[0,1,1], [1,0,1], [1,1,0]],
>>                          size=(1,1,1), symbol='Cu', pbc=(1,1,1))
>>
>>
>> nl = NeighborList([2.6/2.],bothways=False,self_interaction=False)
>> nl.update(atoms)
>> indices, offsets = nl.get_neighbors(0)
>>
>> print indices
>> print offsets
>>
>> [0 0 0 0 0 0]
>> [[ 0  0  1]
>> [ 0  1 -1]
>> [ 0  1  0]
>> [ 1 -1  0]
>> [ 1  0 -1]
>> [ 1  0  0]]
>>
>>
>> John
>>
>> -----------------------------------
>> John Kitchin
>> Assistant Professor
>> Doherty Hall A207F
>> Department of Chemical Engineering
>> Carnegie Mellon University
>> Pittsburgh, PA 15213
>> 412-268-7803
>> http://kitchingroup.cheme.cmu.edu
>> _______________________________________________
>> ase-users mailing list
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>
>