The ABINIT Users Mailing List ( CLOSED )

[<sk00077@surrey.ac.uk>]

Dear all,

I want to obtain the energy levels of the defect states on a Multiwalled CNT
(MCNT).
The defects are produced due to functionalisation and should be like holes in
the
outer wall of the tube (i.e. some carbon atoms missing from their sites). The
edges
of these holes may have some other species (e.g. -COOH, -OH) attached to them
but it is not necessary. I am assuming that (tight binding) DFT is best tool
for this 
purpose.

I am new to DFT and have no idea of which code will be best for my purpose: I
do not need very accurate estimates, I have a high end workstation, have no
local
expert on DFT and am rather short on time. I have come across the book by 
Richard M. Martin  "Electronic Structure: Basic Theory and Practical Methods",
but
it will take some time for me to form my own opinion.

So, could you please guide me a little for the task at hand? Particularly
regarding
following:

1. Whether I should use DFT at all?
    If yes, would abinit be alright for this purpose?
    if no, which other (free) packages should I look at?
2. How much time will it take to simulate say a ~400 atom tube? (this MCNT 
will
  have two concentric tubes of ~200 atoms each and outer tube will have a hole
  of certain size).
3. what can be said about the accuracy of the results? (I am doing experiments
on
  this system so want to compare it).

People have done simulation of defects on the CNTs (I came across only Stone-
Wales defects, and used to study mech. properties). If I missed something I 
would be grateful if you could please point me in right direction.

Thank you very much.
Shishir.