[Pw_forum] band structure for fullerene

[Giuseppe Mattioli]

Dear Unknown User

Fullerene is a molecule, an intrinsically non-periodic object. In a periodic plane-wave framework like that implemented in Quantum ESPRESSO you 
generally treat such systems as "almost isolated" objects, that is, you put the molecule in a large (usually cubic, ibrav=1) supercell, and you check 
that the supercell is so large that the properties of your molecule became insensitive to the supercell dimension. Band structures of such objects are 
nonsense: all the eigenvalues should be flat in the Brillouin zone (and this is a good test to be sure that the molecule does not interact with its 
periodically replicated images). There are also some additional electrostatic tricks to decouple the molecule from its images, see "assume_isolated" 
in the PW manual.

Please sign always your posts to rhis forum with name and affiliation.

HTH

Giuseppe


On Sunday 18 May 2014 23:28:38 Farzad Molani wrote:
> Dear PWSCF users,
> I'm going to draw band structure for fullerene, but I have some problems.
> What is the best ibrav for fullerene? Is ibrav=2 correct?
> in addition, what is the best K-POINT direction for drawing band structure?
> please help me
> best regards


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   Giuseppe Mattioli                            
   CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
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