Background models

KherveFitting offers the standard XPS background subtraction methods, plus a Multi-Regions Smart mode that adapts the choice per region.

Linear

A two-point linear interpolation between the high-BE and low-BE endpoints:

B_L(E) = I_high · (E_low − E) / (E_low − E_high)
        + I_low  · (E − E_high) / (E_low − E_high)

Best for narrow, well-isolated peaks where the inelastic background is small.

Linear background example

Shirley

The default for most C 1s, O 1s, and N 1s core levels. Good for moderate inelastic backgrounds and the de-facto standard for chemical-state fitting.

Shirley background example

Tougaard (single & double)

Physically motivated for large inelastic backgrounds, wide windows, and depth-sensitive analysis. KherveFitting provides both single and double Tougaard variants.

Double Tougaard background

Multi-Regions Smart (default)

Splits the selected window into regions and applies an appropriate background per region — the right choice in most cases.

Practical tips

When…Use
Most chemical-state fits (C 1s, O 1s, N 1s)Shirley
Wide survey-style windows, strong inelastic tailsTougaard
Narrow, isolated peaksLinear
Mixed regions, fast workflowMulti-Regions Smart

Place vertical region lines in flat regions ~1–2 eV away from peaks for the most stable backgrounds. To fine-tune, hold Shift and drag a background endpoint.