xas

This option controls the details of simulating X-ray absorption spectroscopy with target state optimization (TSO) DFT method.

elements

Value

Element list

Default

None

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

1xas
2  elements C N O
3end

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:

 1 xas
 2   elements C
 3   exclude 2-6
 4 end
 5 mol
 6   C                  1.20809735    0.69749533   0.
 7   C                  0.00000000    1.39499067   0.
 8   C                 -1.20809735    0.69749533   0.
 9   C                 -1.20809735   -0.69749533   0.
10   C                 -0.00000000   -1.39499067   0.
11   C                  1.20809735   -0.69749533   0.
12   H                  2.16038781    1.24730049   0.
13   H                  0.00000000    2.49460097   0.
14   H                 -2.16038781    1.24730049   0.
15   H                 -2.16038781   -1.24730049   0.
16   H                  0.00000000   -2.49460097   0.
17   H                  2.16038781   -1.24730049   0.
18 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.