Quick start

This walkthrough mirrors the 13-step quick start in the official manual. It uses the bundled sample file STO.xlsx (SrTiO₃ thin film, Thermo Kalpha) found in the Data/ folder.

1. Instrument settings

Before analysis, set the correct sensitivity factor library. Open Edit → Preferences → Instrument Settings and pick the entry for your instrument:

  • General: C-Al1486 and TPP-2M
  • Thermo Kalpha / Nexsa: A-ALTHERMO1 and TPP-2M
  • Kratos (newer): C-KRATOSF1S - Al1486 and TPP-2M
  • Kratos (older): C-KRATOSC1S - Al1486 and TPP-2M

The X-ray-to-analyser angle defaults to the magic angle (54.7°). Doublet splittings live in C-Al1486 and apply across all instruments.

Preferences window with Instrument Settings tab

2. Open files

Drag any supported XPS file (.xlsx, .vms, .kal, .spe, …) into the plot area. If the file is not already in KherveFitting format, the program creates an Excel file in the correct format with corrected raw data and exported transmission. Multiple files can be dragged at once.

Opening a VAMAS file

For this walkthrough, drag STO.xlsx from the Data folder and use the middle mouse wheel to scroll to the Sr3d core level. Make sure RSF library A-ALTHERMO1 is selected.

3. Plot and core-level control

A few essential shortcuts:

  • Mouse wheel — switch between core levels (or Ctrl+[ / Ctrl+])
  • Ctrl+←/→ — pan along the X axis
  • Ctrl+↑/↓ — zoom Y
  • Ctrl + + / Ctrl + − — zoom X
  • Ctrl+Shift+← — zoom X while keeping the low-BE minimum constant

4. Prepare for peak fitting

Peak fitting screen

Click the peak-fit icon to open the fitting window. It has two tabs: Background and Peak Fitting. Default fitting method is least squares; default model is GL (Area) — adequate for newcomers, but Voigt (Area, L/G, σ) is recommended for physical meaningfulness. LA (Area, σ/γ, γ) is familiar to CasaXPS users.

5. Create a background

Click on the left (high BE) and right (low BE) of the plot, ideally in flat regions 1–2 eV away from peaks, then press Create Region. With Smart or Shirley, a Shirley background is generated and labelled region "1".

Creating a Shirley background

6. Create a peak model

Switch to the Peak Fitting tab. The Sr3d core level is a doublet (~1 eV FWHM, split by ~1.7 eV). Press Add 2 Peaks. Two peaks A and B are created with peak B linked to A:

  • Position A + 1.7 # 0.2 — B is 1.7 eV from A, ±0.2 eV variation
  • FWHM A × 1 — locked equal to A
  • Area A × 0.667 # 0.05 — d-shell ratio (4/6) ±0.05
Adding two SGL peaks for Sr3d

7. Fit the peak model

Press Fit N# times and wait for the iterations. RSD around 2.0–3.4 is acceptable for an SGL fit. You'll see FWHM ~1.0 eV and L/G ~62 %.

Two SGL peaks fitted

Sharper peaks tend more Lorentzian; broader peaks tend more Gaussian. Avoid fixing shape at 30 % across all peaks.

8. Move the peak model

Press Tab or Q to select peak A. With the cursor on the cross marker, drag A — peak B follows because it's linked. To move B alone, drag B directly. Alt + arrow keys also nudge a selected peak.

9. Other models — LA and Voigt

Remove the SGL pair, switch to LA, fit again — RSD ~1.8–2.4. The LA model is a full Lorentzian powered on the right by γ and on the left by σ; σ/γ controls asymmetry (50 % = symmetric).

LA model peak grid

Switch to Voigt and refit — RSD ~2.9–3.1. Unlike GL/LA, the Voigt FWHM cannot be constrained directly: you constrain Gaussian width and L/G ratio, and the Lorentzian width follows. Rules of thumb:

  • FWHM 1.0–1.5 eV ⇒ L/G ~20 %
  • FWHM > 1.5 eV ⇒ L/G ~10–20 %
  • FWHM < 1.0 eV ⇒ L/G rises sharply to 50–60 %
Voigt model peak grid

Repeat the fit on Ti2p with the Voigt model. KherveFitting does not lock B's FWHM to A for Ti2p / V2p — Ti2p₁/₂ is broader than Ti2p₃/₂ for oxides due to the Köster-Kronig effect.

Ti2p Voigt fit

10. Export to Results Grid

With the correct RSF library set, press the Export icon to push the fit to the Results grid. Tick Ti2p₃/₂ and Sr3d₅/₂ to compare atomic concentrations.

Results Grid showing atomic concentrations

11. Load a peak table

Saved peak tables are JSON. Scroll to C 1s, press Load Peaks Parameter in the horizontal toolbar, and pick C1s_C-C_4peaks_Voigt_GK_xxxx.json. Four peaks appear in the fitting grid. Place a Shirley background, fit — RSD around 1 should result.

Repeat on O 1s with O1s_O-Lat_3peaks_Voigt_GK_xxxx.json (background between 527.3 and 535 eV; the O-surf peak is often negligible and can be removed).

12. Binding energy correction

KherveFitting looks for a peak named C1s C-C and computes the offset to 284.8 eV (this target is configurable in Preferences → Instrument Settings). Click the green BE-correction button — every peak in the fitting and Results grids shifts by the same amount. Type 0.00 and click the plot to revert.

C1s aligned to 284.8 eV

13. Background offset

Scroll to O 1s, zoom down with Ctrl+↓ to background level. On the Background tab, reset vertical lines, choose 527.3–537.5 eV, hold Shift, and drag the high-BE side of the background down to fine-tune.

What's next