[SIESTA-L] Confusion about basis.

Thu, 19 May 2011 07:53:03 -0700 

Dear All,


At this stage , I simply can practice those examples which comes along with
SIESTA.   I came across one confusing problem:


For graphene,    they use the basis like:

%block PAO.Basis
C    2     -0.12072
  n=2   0   1   E   128.52695     3.40412
      3.91719
  n=2   1   1   E    76.78391     3.23752
      4.11407
%endblock PAO.Basis


While for C60,  the basis is adopted like:

%block PAO.Basis                 # Define Basis set
C     3      0.01
 n=2    0    2   E     69.86      4.68
   6.004   4.195
   1.000   1.000
 n=2    1    2   E     18.95      3.78
   4.995   3.100
   1.000   1.000
 n=3    2    1   E     16.84      0.05
   4.187
   1.000
%endblock PAO.Basis


Got confused about them.   Basically  both of them consist of C atoms.  what
is the deeper reason that they are so different?


thanks


Lily

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