# XANES Absolute cross-section

The absolute cross section can be obtained from the output in ‘xmu.dat’. Look for this line:

```xsedge+100, used to normalize mu             2.5908E-04
```

Since our distances are in $\AA$, we report cross section also in $\AA^2$. If you multiply the 4-th or 5-th column by this normalization value you will obtain the cross section in $\AA^2$. Often the absolute cross section is reported in barns, which have a simple connection with our units (1 $\AA^2$ = 100Mbarn).

Note that this normalization can be switched off using the ABSOLUTE card. This is set by default for ELNES and EXELFS calculation. The normalization factor will then show as "1.0".

### Calculation Strategies and Examples

XANES calculations

1. Need for SCF and additional difficulties for XANES
2. GeCl4 Molecule
3. Solid: XANES and LDOS
4. Absolute cross-section