xas

elements

Value	Element list
Default	None

A list of heavy elements whose XAS is to be calculated. For example,

xas
  elements C N O
end

Then, Qbics will calculate 3 XAS for C, N, and O, respectively.

num_states

Value	An integer
Default	1

The number of excited states for each core electron to be calculated.

exclude

Value	Atom range
Default	None

By default, Qbics will calculate the core excitations of all atoms for a given element. For example:

xas
  elements C 
  exclude 2-6
end
mol
  C                  1.20809735    0.69749533   0.
  C                  0.00000000    1.39499067   0.
  C                 -1.20809735    0.69749533   0.
  C                 -1.20809735   -0.69749533   0.
  C                 -0.00000000   -1.39499067   0.
  C                  1.20809735   -0.69749533   0.
  H                  2.16038781    1.24730049   0.
  H                  0.00000000    2.49460097   0.
  H                 -2.16038781    1.24730049   0.
  H                 -2.16038781   -1.24730049   0.
  H                  0.00000000   -2.49460097   0.
  H                  2.16038781   -1.24730049   0.
end

Without exclude, Qbics will calculate core excitations all 6 C atoms. But since the 6 C atoms are equivalent, this is unnecessary. So, in exclude we assign atom 2,3,4,5,6, meaning that the calculation of core excitations of these 5 atoms are skipped.