Energy Calibration
The preprocessing module corrects the binding energy axis using a reference peak
of known position. This compensates for charging effects and instrument drift.
Theory
XPS binding energies are referenced to the Fermi level. Surface charging in insulating samples causes an offset \(\Delta E\) that must be corrected:
\[
E_b^{\text{(corrected)}} = E_b^{\text{(measured)}} + \Delta E
\]
where:
\[
\Delta E = E_{\text{ref}}^{\text{(literature)}} - E_{\text{ref}}^{\text{(observed)}}
\]
Common reference peaks:
| Reference | Literature Energy (eV) |
|---|---|
| C 1s (adventitious) | 284.8 |
| Au 4f\(\_{7/2}\) | 84.0 |
| Ag 3d\(\_{5/2}\) | 368.2 |
| Cu 2p\(\_{3/2}\) | 932.7 |
API Reference
calibrate_spectrum
from xps_analyzer.preprocessing import calibrate_spectrum
calibrated = calibrate_spectrum(
spectrum=c1s,
reference_element="C 1s",
reference_energy=284.8
)
Parameters:
| Parameter | Type | Description |
|---|---|---|
spectrum |
XPSSpectrum |
Spectrum to calibrate |
reference_element |
str |
Region name of the reference peak |
reference_energy |
float |
Literature binding energy in eV |
Returns: A new XPSSpectrum with shifted energy axis.
calibrate_sample
from xps_analyzer.preprocessing import calibrate_sample
calibrated_sample = calibrate_sample(
sample=sample,
reference_element="C 1s",
reference_energy=284.8
)
Applies calibrate_spectrum to all spectra in a dataset or sample, propagating the
same energy shift throughout.