Rhenium

Re 4f7/2 binding energy values [1].

Re 4f7/2 - 4f5/2 splitting: 2.41 eV +/- 0.01 eV, [2] sets it at 2.43 eV
Re 5s: 99 eV
Re 4d5/2: 260 eV
Re 4d3/2: 274 eV
Re 4p3/2: 446 eV
Re 4p1/2: 518 eV
Re 4s: 625 eV

Re 4f spectrum of sputter cleaned Re metal.

Peakshape for Re 4f peaks from a Re metal standard in the figure above is LA(1.16,3,10).

Re 4d spectrum of sputter cleaned Re metal.

Peakshape for Re 4d peaks from a Re metal standard in the figure above is GL(80).

References:
[1] C.D. Wagner, A.V. Naumkin, A. Kraut-Vass, J.W. Allison, C.J. Powell, J.R.Jr. Rumble, NIST
Standard Reference Database 20, Version 3.4 (web version) (http:/srdata.nist.gov/xps/) 2003.
[2] J.F. Moulder, W.F. Stickle, P.E. Sobol, K.D. Bomben, Handbook of X-ray Photoelectron Spectroscopy, Perkin-Elmer Corp., Eden Prairie, MN, 1992.

Rubidium

Rb 3d5/2 binding energies.

Rb 3d5/2 - 3d3/2 splitting: ~ 1.48 eV
Rb 3p3/2: 240 eV
Rb 3p1/2: 249 eV
Rb 3s: 325 eV
Rb 4p: 16 eV
Rb 4s: 31 eV

Reference:
[1] J.F. Moulder, W.F. Stickle, P.E. Sobol, K.D. Bomben, Handbook of X-ray Photoelectron Spectroscopy, Perkin-Elmer Corp, Eden Prairie, MN, 1992.

Potassium

K 2p3/2 binding energies.

K 2p3/2-1/2 splitting is 2.77 to 2.8 eV.

Notes: Often will see K 2p peaks in high resolution C 1s spectra. Be careful not to confuse these peaks with contributions from C 1s fluorocarbon peaks or pi -> pi* shake-up structure.

For quantification in survey scans it is often easier to use the K 2s peak (~380 eV) as the K 2p peak may not be fully separated from the C 1s peak at lower resolutions.

Neon, Argon, Krypton and Xenon

Noble gases are usually only observed when they have been implanted in materials - such as when sputtering using an ion beam.  Relevant binding energies below [1].

Ne 1s: 861.6 - 863.4 eV
Ne 2s: ~ 41 eV

Ar 2p3/2: 240.3 - 241.9 eV
Ar 2p3/2 - 2p1/2 splitting is 2.12 eV
Ar 2s: ~ 320 eV
Ar 3s: ~ 24 eV

Kr 3d5/2: ~ 87 eV
Kr 3d5/2-3d3/2 splitting is 1.23 eV
Kr 3p3/2: ~ 208 eV
Kr 3p1/2: ~ 216 eV
Kr 4s: ~ 21 eV

Xe 3d5/2: 668.9 - 674.1 eV
Xe 3d5/2 - 3d3/2 splitting is 12.67 eV
Xe 3p3/2: ~ 943 eV
Xe 3p1/2: ~ 996 eV
Note that MNN Auger structure overlaps the 3p3/2 peak (when using an Al X-ray source)
Xe 4d 5/2: ~ 61 eV
Xe 4d 3/2: ~ 63 eV
Xe 4p: ~ 139 eV
Xe 4s: ~ 207 eV
Xe 3s: ~ 1141 eV

Reference:
[1] J.F. Moulder, W.F. Stickle, P.E. Sobol, K.D. Bomben, Handbook of X-ray Photoelectron Spectroscopy, Perkin-Elmer Corp, Eden Prairie, MN, 1992.

2019 Surface Science Western XPS Short Course Presentations

Presentations from our recent XPS Short Course

Short Course Introduction Slides

Introduction to Oxide Chemical State Analysis

Advanced Chemical State Analysis

Auger Parameter and Wagner Plots

Bad Data Fitting...

Gold

The Au 4f7/2 ISO standard binding energy for metallic gold used for calibration is 83.96 eV (for monochromatic Al K(alpha) X-rays).
Typical fitting parameters for pure sputter cleaned gold (10 eV pass energy) include:
FWHM ~ 0.59 eV, GL(86) peak-shape

Au 4f7/2 - Au 4f5/2 splitting ~ 3.67 eV

Au 4f XPS spectrum of sputtered cleaned gold.

The Use and Misuse of Curve Fitting in the Analysis of Core X-ray Photoelectron Spectroscopic Data

Peter Sherwood at the University of Washington has recently published a very good review article [1] that goes through many of the issues and pitfalls associated with achieving meaningful results from curve fitting XPS spectra.  It also includes a useful tutorial section that uses the W 4f spectrum of oxidized tungsten to illustrate the methods outlined in the paper.  A good starting point read for those who are getting into curve-fitting of XPS spectra (and for those needing a refresher!).

Reference:
[1] Peter M.A. Sherwood, The use and misuse of curve fitting in the analysis of core X‐ray photoelectron spectroscopic data, Surf. Interface Anal. 51 (2019) 589-610.

Advanced Analysis of Copper X-ray Photoelectron Spectra

This recent paper [1] builds upon and extends previously published X-ray photoelectron spectroscopy (XPS) curve-fitting and data analysis procedures [2,3] for a wide range of copper containing species. Steps undertaken include: 1) an examination of existing Cu 2p3/2 main peak and Cu 2p3/2 - Cu L3M4,5M4,5 Auger parameter literature data, 2) analysis of a series of quality standard samples, 3) curve-fitting procedures for both the Cu 2p3/2 and the Cu L3M4,5M4,5 spectra (as well as associated anions), 4) calculations that determine the amount of Cu(II) species in a mixed oxidation state system, 5) calculations and necessary data for thin film mixed oxide/hydroxide thickness measurements and 6) a presentation of literature and standard sample values in a Wagner (chemical state) plot.

Some examples of the extensive datasets and spectra available in this paper are presented below.

Cu 2p3/2 spectra of various Cu(II) species.

Cu L3M4,5M4,5 spectra for (left) Cu(0), Cu(I) species, mineral samples, and (right) Cu(II) species.

Curve-fitted Cu L3M4,5M4,5 spectrum of wrought copper sample submerged in an Ar aerated 3M NaCl solution for 30 days.  Curve-fitting results suggest 22 % Cu(0), 65 % Cu2O and 13% Cu2S.

Cu 2p3/2 - Cu L3M4,5M4,5 Wagner (chemical state) plot with literature and standard sample data.

Cu 2p3/2 and Cu 2p3/2 - Cu L3M4,5M4,5 Auger parameter literature values from Cu species

Cu 2p3/2 (main peak only) and Cu 2p3/2 - Cu L3M4,5M4,5 Auger parameter values from standard samples (20 eV pass energy). a) 932.63 eV for non-monochromatic Al X-ray source, 932.62 eV for monochromatic Al K(alpha) X-ray source b) Note that this value is specified for the Kratos instruments used in this work. Other instruments may not have this accuracy. This will also not apply for Cu(0) in a non-conductive environment where calibration to other peaks are needed (e.g. adventitious carbon C 1s which has an error of 0.1 to 0.2 eV associated with it).

Reference:
[1] M.C. Biesinger, Advanced Analysis of Copper X-ray Photoelectron (XPS) Spectra, Surf. Interface Anal. 49 (2017) 1325-1334.
[2] M.C. Biesinger, L.W.M. Lau, A.R. Gerson, R.St.C. Smart, Appl. Surf. Sci. 257 (2010) 887-898.
[3] M.C. Biesinger, B.R. Hart, R. Polack, B.A. Kobe, R.St.C. Smart, Miner. Eng. 20 (2007) 152.

Germanium

Ge 3d binding energy values.

Ge 3p3/2 binding energy values.

Ge 3d - L3M45M45 Auger Parameter values.

Notes:
Ge 3d5/2-3/2 splitting is 0.59 eV
Ge 3p3/2-1/2 splitting is 4.18 eV
Ge 3s: 181 eV
Ge 2p3/2: 1217 eV
Ge 2p1/2: 1248 eV

XPS survey spectrum of germanium (Al K(alpha) X-ray source).

Calcium

Ca 2p3/2 binding energy values.

Notes:
Ca 2p3/2-2p1/2 splitting is 3.55 eV (for CaCO3).
In survey spectra of samples where magnesium is also present there can be an overlap of the Ca 2p region with Mg KLL structure.  In these cases it is better to use the Ca 2s peak for quantification. 

Standards taken at Surface Science Western.
CaPO4
Ca 2p3/2: 347.3 eV
P 2p3/2: 133.2 eV
P 2s: 190.7 eV
O 1s: 531.1 eV

CaCO3
Ca 2p3/2: 346.5-347.0 eV
O 1s: 531.1 eV
C 1s (CO3): 289.2-289.4 eV

CaSO4
Ca 2p3/2: 348.3 eV
O 1s: 532.5 eV
S 2p3/2: 169.6 eV

Gypsum (CaSO4 . 2H2O)
Ca 2p3/2: 348.1-348-3 eV
O 1s (SO4): 532.1- 532.4 eV; O 1s (H2O) 533.4 - 533.5 eV
S 2p3/2: 169.3eV

Ca 2p spectrum of CaSO4.