Basic XPS Information Section

The Basic XPS Information Section provides fundamental XPS spectra, BE values, FWHM values, BE tables, overlays of key spectra, histograms and a table of XPS parameters.
The Advanced XPS Information Section is a collection of additional spectra, overlays of spectra, peak-fit advice, data collection guidance, material info,
common contaminants, degradation during analysis, auto-oxidation, gas capture study, valence band spectra, Auger spectra, and more.
Published literature references, and website links are summarized at the end of the advanced section.
→  Periodic Table – HomePage                     XPS Database of Polymers                       → Six (6) BE Tables

 

Thorium (Th)

 

Thorianite – ThO2 Thorium Metal – Tho Thorite – Th(SiO4)

 

  Page Index
  • Expert Knowledge Examples & Explanations


Thorium (Tho) Metal

Peak-fits, BEs, FWHMs, and Peak Labels

.
Thorium (Tho) Metal
Th (4f) Spectrum – raw spectrum
ion etched clean		 Thorium (Tho) Metal
Peak-fit of Th (4f) Spectrum
w/o asymm
→  Periodic Table – HomePage  
Thorium (Tho) Metal
Th (4f) Spectrum – extended range 
 Thorium (Tho) Metal
Peak-fit of Th (4f) Spectrum (w asymm)
   
   
 

Survey Spectrum of Thorium (Tho) Metal
with Peaks Integrated, Assigned and Labelled

 

 
→  Periodic Table 

XPS Signals for Thorium, (Tho) Metal

Spin-Orbit Term,  BE (eV) Value, and Scofield σ for Aluminum Kα X-rays (1486 eV, 8.33 Ang)

Overlaps Spin-Orbit Term BE (eV) Value Scofield σ from 1486 eV X-rays IMFP (TPP-2M) in Å
Th (4p1/2) 1170 1.80 11.14
Th 4p3/2) 966 7.46 15.29
Fe (2p) overlaps Th (4d3/2) 713 10.82 20.24
Th (4d5/2) 676 16.31 20.94
Ca (2p) overlaps Th (4f5/2) 343 18.81 27.01
Th (4f7/2) 333 23.94 27.17
C (1s) overlaps Th (5s) 290 0.702 27.97
S (2s) overlaps Th (5p1/2) 230 0.660 29.02
Zr (3d) overlaps Th (5p3/2) 177 2.05 29.86

σ:  abbreviation for the term Scofield Photoionization Cross-Section which is used together with IMFP and TF to produce atom% quantitation

Plasmon Peaks

Energy Loss Peaks

Auger Peaks

 

Energy Loss    Intrinsic Plasmon Peak:  ~xx eV above peak max
Expected Bandgap for ThO2: 3.5 – 4.5 eV  (https://materialsproject.org/)
Work Function for Th:  xx eV
*Scofield Cross-Section (σ) for C (1s) = 1.0

→  Periodic Table 

 

Valence Band Spectrum from
Fresh Native Oxide of Tho Metal
 Fresh exposed bulk produced by extensive Ar+ ion etching – Ion Etched Thorium rapidly reacts w gases in UHV

 

 

Plasmon Peaks from Thorium, Tho Metal
 Fresh exposed bulk produced by extensive Ar+ ion etching

Th (4f) – Extended Range Spectrum Th (4f) – Extended Range Spectrum – Vertically Zoomed
→  Periodic Table 
 

Th (MNN) Auger Peaks from Thorium, Tho Metal
 Fresh exposed bulk produced by extensive Ar+ ion etching
Tho Metal – main Auger peak Tho Metal – full Auger range

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 
 

Artefacts Caused by Argon Ion Etching

C (1s) from Metal Carbide(s)

can form when ion etched Reactive Metal Surfaces capture
Residual UHV Gases (CO, H2O, CH4 etc)

Argon Trapped in Tho

can form when Argon Ions are used
to removed surface contamination
 

Side-by-Side Comparison of
Th Native Oxide & Thorium Oxide (ThO2)
Peak-fits, BEs, FWHMs, and Peak Labels
Th Native Oxide Thorium Oxide, ThO2
Th (4f) from Th Native Oxide
Flood Gun OFF
As-Measured, C (1s) at 285.7 eV 		 Th (4f) from ThO2 
Flood Gun ON
Charge Referenced to C (1s) at 285.0 eV


→  Periodic Table 
   
Th Native Oxide Thorium Oxide, ThO2
C (1s) from Th Native Oxide
As-Measured, C (1s) at 285.7 eV
Flood Gun OFF

C (1s) from ThO2 
Flood Gun ON
Charge Referenced to C (1s) at 285.0 eV

→  Periodic Table 
  . 
Th Native Oxide Thorium Oxide, ThO2
O (1s) from Th Native Oxide
As-Measured, C (1s) at 285.7 eV
Flood Gun OFF

O (1s) from ThO2
Flood Gun ON
Charge Referenced to C (1s) at 285.0 eV
→  Periodic Table

 

 

Survey Spectrum of Th Native Oxide
with Peaks Integrated, Assigned and Labelled

 

→  Periodic Table 

 


Survey Spectrum of Thorium Oxide, ThO2
with Peaks Integrated, Assigned and Labelled

 

 

 

 


→  Periodic Table  

Overlays of Th (4f) Spectra for:
Tho metal, Th Native Oxide and ThO2

Caution: BEs from Grounded Native Oxides can be Misleading if Flood Gun is ON

 

 Overlay of Tho metal and Th Native Oxide – Th (4f)
Native Oxide C (1s) = 285.7 eV (Flood gun OFF)

  Overlay of Tho metal and ThO2 – Th (4f) 
Pure Oxide C (1s) = 285.0 eV
Chemical Shift:  1.1 eV
→  Periodic Table  Copyright ©:  The XPS Library 

 

Overlay of Th (4f)
Tho Metal, Th Native Oxide, & ThO2

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Valence Band Spectra
Th native oxide, ThO2

Th native oxide
 Thorium Oxide, ThO2
Flood gun is ON,  Charge referenced so C (1s) = 285.0 eV

Overlay of Valence Band Spectra for:
Th native oxide and ThO2

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Thorium Minerals, Gemstones, and Chemical Compounds

 
Thorbastnsite – ThCa(CO3)2F2-3H2O Ekanite – Ca2ThSi8O20 Nuragheite – Th(MoO4)2 · H2O Huttonite – ThSiO4

→  Periodic Table 

 

Six (6) Chemical State Tables of Th (4f7/2) BEs

 

  • The XPS Library Spectra-Base
  • PHI Handbook
  • Thermo-Scientific Website
  • XPSfitting Website
  • Techdb Website
  • NIST Website

→  Periodic Table 

 

Notes of Caution when using Published BEs and BE Tables from Insulators and Conductors:

  • Accuracy of Published BEs
    • The accuracy depends on the calibration BEs used to calibrate the energy scale of the instrument.  Cu (2p3/2) BE can vary from 932.2 to 932.8 eV for old publications 
    • Different authors use different BEs for the C (1s) BE of the hydrocarbons found in adventitious carbon that appears on all materials and samples.  From 284.2 to 285.3 eV
    • The accuracy depends on when the authors last checked or adjusted their energy scale to produce the expected calibration BEs
  • Worldwide Differences in Energy Scale Calibrations
    • For various reasons authors still use older energy scale calibrations 
    • Some authors still adjust their energy scale so Cu (2p3/2) appears at 932.2 eV or 932.8 eV because this is what the maker taught them
    • This range causes BEs in the higher BE end to be larger than expected 
    • This variation increases significantly above 600 eV BE
  • Charge Compensation
    • Samples that behave as true insulators normally require the use of a charge neutralizer (electron flood gun with or without Ar+ ions) so that the measured chemical state spectra can be produced without peak-shape distortions or sloping tails on the low BE side of the peak envelop. 
    • Floating all samples (conductive, semi-conductive, and non-conductive) and always using the electron flood gun is considered to produce more reliable BEs and is recommended.
  • Charge Referencing Methods for Insulators
    • Charge referencing is a common method, but it can produce results that are less reliable.
    • When an electron flood gun is used, the BE scale will usually shift to lower BE values by 0.01 to 5.0 eV depending on your voltage setting. Normally, to correct for this flood gun induced shift, the BE of the hydrocarbon C (1s) peak maximum from adventitious carbon is used to correct for the charge induced shift.
    • The hydrocarbon peak is normally the largest peak at the lowest BE. 
    • Depending on your preference or training, the C (1s) BE assigned to this hydrocarbon peak varies from 284.8 to 285.0 eV.  Other BEs can be as low as 284.2 eV or as high as 285.3 eV
    • Native oxides that still show the pure metal can suffer differential charging that causes the C (1s) and the O (1s) and the Metal Oxide BE to be larger
    • When using the electron flood gun, the instrument operator should adjust the voltage and the XY position of the electron flood gun to produce peaks from a strong XPS signal (eg O (1s) or C (1s) having the most narrow FWHM and the lowest experimentally measured BE. 

→  Periodic Table 

Table #1

Th (4f7/2) Chemical State BEs from:  “The XPS Library Spectra-Base”

C (1s) BE = 285.0 eV for TXL BEs
and C (1s) BE = 284.8 eV for NIST BEs

Element Atomic # Compound As-Measured by TXL or NIST Average BE Largest BE Hydrocarbon C (1s) BE  Source
Th 90 Th – element 332.9 eV 285.0 eV The XPS Library
Th 90 Th-(OH)3 285.0 eV The XPS Library
Th 90 Th-CO3 285.0 eV The XPS Library
Th 90 Th-O2 334.1 eV 285.0 eV The XPS Library
Th 90 Th-F4 336.5 eV 285.0 eV The XPS Library

Charge Referencing Notes

  • (N*number) identifies the number of NIST BEs that were averaged to produce the BE in the middle column.
  • The XPS Library uses Binding Energy Scale Calibration with Cu (2p3/2) BE = 932.62 eV and Au (4f7/2) BE = 83.98 eV.  BE (eV) Uncertainty Range:  +/- 0.2 eV
  • Charge Referencing of insulators is defined such that the Adventitious Hydrocarbon C (1s) BE (eV) = 285.0 eV.  NIST uses C (1s) BE = 284.8 eV 
  • Note:   Ion etching removes adventitious carbon, implants Ar (+), changes conductivity of surface, and degrades chemistry of various chemical states.
  • Note:  Ion Etching changes BE of C (1s) hydrocarbon peak.
  • TXL – abbreviation for: “The XPS Library” (https://xpslibrary.com).  NIST:  National Institute for Science and Technology (in USA)

→  Periodic Table 

Table #2

Th (4f7/2) Chemical State BEs from:  “PHI Handbook”

C (1s) BE = 284.8 eV

→  Periodic Table 

Copyright ©:  Ulvac-PHI

Table #3

Th (4f7/2) Chemical State BEs from:  “Thermo-Scientific” Website

C (1s) BE = 284.8 eV

 

No BE Table for Thorium

→  Periodic Table 

Copyright ©:  Thermo Scientific 

Table #4

Th (4f7/2) Chemical State BEs from:  “XPSfitting” Website

Chemical State BE Table derived by Averaging BEs in the NIST XPS database of BEs
C (1s) BE = 284.8 eV

 

No BE Table for Thorium

→  Periodic Table 

Copyright ©:  Mark Beisinger

Table #5

Th (4f7/2) Chemical State BEs from:  “Techdb.podzone.net” Website

 

XPS Spectra – Chemical Shift | Binding Energy
C (1s) BE = 284.6 eV

XPS(X線光電子分光法)スペクトル 化学状態 化学シフト ケミカルシフト

Element Level Compound B.E.(eV) min max
Th 4f7/2 Th 332.9 ±0.3 332.6 ～ 333.2
Th 4f7/2 ThO2 334.5 ±0.4 334.1 ～ 334.8
Th 4f7/2 ThF4 336.6 ±0.4 336.2 ～ 336.9
Th 4d5/2 Th 675.3 ±0.3 675.0 ～ 675.6
Th 4d5/2 ThO2 675.5 ±0.3 675.2 ～ 675.7

→  Periodic Table 

 


Histograms of NIST BEs for Th (4f7/2) BEs

Important Note:  NIST Database defines Adventitious Hydrocarbon C (1s) BE = 284.8 eV for all insulators.

 

Histogram indicates:  333.3 eV for Tho based on 5 literature BEs Histogram indicates:  336.1 eV for ThO2 based on 2 literature BEs

Histogram indicates:  xxx eV for Thx based on xx literature BEs

Table #6


NIST Database of Th (4f7/2) Binding Energies

NIST Standard Reference Database 20, Version 4.1

Data compiled and evaluated
by
Alexander V. Naumkin, Anna Kraut-Vass, Stephen W. Gaarenstroom, and Cedric J. Powell
©2012 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

Important Note:  NIST Database defines Adventitious Hydrocarbon C (1s) BE = 284.8 eV for all insulators.

 

Element Spectral Line Formula Energy (eV) Reference
Th 4f7/2 Th 333.10  Click
Th 4f7/2 Th 333.10  Click
Th 4f7/2 Th 333.10  Click
Th 4f7/2 Th 333.25  Click
Th 4f7/2 Th 333.80  Click
Th 4f7/2 ThO2 334.60  Click
Th 4f7/2 ThO2 334.70  Click
Th 4f7/2 ThBr4 335.00  Click
Th 4f7/2 ThCl4 335.70  Click
Th 4f7/2 ThCl4 335.70  Click
Th 4f7/2 ThF4 336.45  Click
Th 4f7/2 ThF4 336.90  Click
Th 4f7/2 ThF4 336.90  Click
Th 4f7/2 ThO2 337.70  Click

 

 

Statistical Analysis of Binding Energies in NIST XPS Database of BEs

 

 

→  Periodic Table 

 


Advanced XPS Information Section

 

Expert Knowledge, Spectra, Features, Guidance and Cautions
for XPS Research Studies on Thorium Materials

 

 

 

Expert Knowledge Explanations

 

→  Periodic Table 

 

 

Thorium Chemical Compounds


Peak-fits and Overlays of Chemical State Spectra

Pure Thorium:  Th (4f)
Cu (2p3/2) BE = 932.6 eV		 ThO2:  Th (4f)
C (1s) BE = 285.0 eV		 ThF4:  Th (4f)
C (1s) BE = 285.0 eV

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

Overlay of Th (4f) Spectra shown Above

C (1s) BE = 285.0 eV

 

Chemical Shift between Th and ThO2:  1.2eV
 Chemical Shift between Th and ThF4:  3.6 eV

 

→  Periodic Table 

 

Thorium Oxide (ThO2)
pressed powder

Survey Spectrum from ThO2
Flood gun is ON, C (1s) BE = 285.0 eV
 Th (4f) Chemical State Spectrum from ThO2
Flood gun is ON, C (1s) BE = 285.0 eV
  . 
O (1s) Chemical State Spectrum from ThO2
Flood gun is ON, C (1s) BE = 285.0 eV
 C (1s) Chemical State Spectrum from ThO2
Flood gun is ON, C (1s) BE = 285.0 eV
  . 
Valence Band Spectrum from ThO2
Flood gun is ON, C (1s) BE = 285.0 eV
  


Shake-up Features
for ThO2

Th (4f) Extended Range

 

 

Multiplet Splitting Features for Thorium Compounds

Th metal – NO Splitting ThO2 – Multiplet Splitting Peaks
na na

 

 

Features Observed

  • xx
  • xx
  • xx

→  Periodic Table 

 

 

 

Thorium Chemical Compounds

 

Thorium Tetrafluoride, ThF4

Survey Spectrum of ThF4 Th (4f) Spectrum of ThF4
.
C (1s) Spectrum of ThF4 F (1s) Spectrum of ThF4
.
Valence Band Spectrum of ThF4

→  Periodic Table 

 

Quantitation Details and Information

 

Quantitation by XPS is often incorrectly done, in many laboratories, by integrating only the main peak, ignoring the Electron Loss peak, and the satellites that appear as much as 30 eV above the main peak.  By ignoring the electron loss peak and the satellites, the accuracy of the atom% quantitation is in error.

When using theoretically calculated Scofield cross-section values, the data must be corrected for the transmission function effect, use the calculated TPP-2M IMFP values, the pass energy effect on the transmission function, and the peak area used for calculation must include the electron loss peak area, shake-up peak area, multiplet-splitting peak area, and satellites that occur within 30 eV of the main peak.

 

Quantitation from Pure, Homogeneous Binary Compound
composed of Thorium – ThO2

 

This section is focused on measuring and reporting the atom % quantitation that results by using:

  • Scofield cross-sections,
  • Spectra corrected to be free from Transmission Function effects
  • A Pass Energy that does not saturate the detector system in the low KE range (BE = 1000-1400 eV)
  • A focused beam of X-ray smaller than the field of view of the lens
  • An angle between the lens and the source that is ~55 deg that negates the effects of beta-asymmetry
  • TPP-2M inelastic mean free path values, and
  • Either a linear background or an iterated Shirley (Sherwood-Proctor) background to define peak areas

The results show here are examples of a method being developed that is expected to improve the “accuracy” or “reliability” of the atom % values produced by XPS.

→  Periodic Table 

 

Thorium Alloys

   
XxCu XxCu
→  Periodic Table   
XxCu XxCu

 

Copyright ©:  The XPS Library 

 

 

 

XPS Facts, Guidance & Information

→  Periodic Table 

    Element Thorium (Th)
  
    Primary XPS peak used for Peak-fitting: Th (4f7/2)  
    Spin-Orbit (S-O) splitting for Primary Peak: Spin-Orbit splitting for “F” Orbital, ΔBE = 9.4 eV
  
    Binding Energy (BE) of Primary XPS Signal: 333 eV
  
    Scofield Cross-Section (σ) Value: Th (4f7/2) = 23.94.     Th (3d5/2) = 18.81
  
    Conductivity: Th resistivity =  
Native Oxide suffers Differential Charing		  
    Range of Th (4f7/2) Chemical State BEs: 332 – 337 eV range   (Tho to ThF4)  
Signals from other elements that overlap
Th (4f7/2) Primary Peak:		   xx (xx)
Bulk Plasmons:   ~xx eV above peak max for pure
Shake-up Peaks: xx
Multiplet Splitting Peaks:   xx

 

 

 General Information about
XXX Compounds:		   xx  
Cautions – Chemical Poison Warning

xx 

Copyright ©:  The XPS Library 

→  Periodic Table 

 

Information Useful for Peak-fitting Th (4f7/2)

 

  • FWHM (eV) of Th (4f7/2) for Pure Tho :  ~0.96 eV using 25 eV Pass Energy after ion etching:
  • FWHM (eV) of Th (4f7/2) for ThO2:  ~1.6 eV using 50 eV Pass Energy  (before ion etching)
  • Binding Energy (BE) of Primary Signal used for Measuring Chemical State Spectra:  333 eV for Th (4f7/2) with +/- 0.2 uncertainty
  • List of XPS Peaks that can Overlap Peak-fit results for Th (4f7/2):  xxxx

→  Periodic Table 

 

General Guidelines for Peak-fitting XPS Signals

 

  • Typical Energy Resolution for Pass Energy (PE) setting used to measure Chemical State Spectra on Various XPS Instruments
    • Ag (3d5/2) FWHM (eV) = ~0.90 eV for PE 50 on Thermo K-Alpha
    • Ag (3d5/2) FWHM (eV) = ~1.00 eV for PE 80 on Kratos Nova
    • Ag (3d5/2) FWHM (eV) = ~0.95 eV for PE 45 on PHI VersaProbe
    • Ag (3d5/2) FWHM (eV) = ~0.85 eV for PE 50 on SSI S-Probe
  • FWHM (eV) of Pure Elements: Ranges from 0.4 to 1.0 eV across the periodic table
  • FWHM of Chemical State Peaks in any Chemical Compound:  Ranges from 1.1 to 1.6 eV  (in rare cases FWHM can be 1.8 to 2.0 eV)
  • FWHM of Pure Element versus FWHM of Oxide:  Pure element FWHM << Oxide FWHM  (e.g. 0.8 vs 1.5 eV, roughly 2x)
  • If FWHM Greater than 1.6 eV:  When a peak FWHM is larger than 1.6 eV, it is best to add another peak to the peak-fit envelop.
  • BE (eV) Difference in Chemical States: The difference in chemical state BEs is typically 1.0-1.3 eV apart.  In rare cases, <0.8 eV.
  • Number of Peaks to Use:  Use minimum. Do not use peaks with FWHM < 1.0 eV unless it is a or a conductive compound.
  • Typical Peak-Shape:  80% G: 20% L,   or Voigt : 1.4 eV Gaussian and 0.5 eV Lorentzian
  • Spin-Orbit Splitting of Two Peaks (due to Coupling):  The ratio of the two (2) peak areas must be constrained.
  • Constraints used on Peak-fitting: typically constrain the peak area ratios based on the Scofield cross-section values
  • Asymmetry for Conductive materials:  20-30% with increased Lorentzian %
  • Peak-fitting “2s” or “3s” Peaks:  Often need to use 50-60% Lorentzian peak-shape

Notes:

  • Other Oxidation States can appear as small peaks when peak-fitting
  • Pure element signals normally have asymmetric tails that should be included in the peak-fit.
  • Gaseous state materials often display asymmetric tails due to vibrational broadening.
  • Peak-fits of C (1s) in polymers include an asymmetric tail when the energy resolution is very high.
  • Binding energy shifts of some compounds are negative due to unusual electron polarization.

→  Periodic Table 

 

Contaminants Specific to Thorium

 

  • Thorium develops a thick native oxide due to the reactive nature of clean Thorium .
  • The native oxide of Th Ox is 5-9 nm thick.
  • Thorium thin films often have a low level of iron (Fe) in the bulk as a contaminant or to strengthen the thin film
  • Thorium forms a low level of Carbide when the surface is ion etched inside the analysis chamber

 

Commonplace Contaminants

 

  • Carbon and Oxygen are common contaminants that appear on nearly all surfaces. The amount of Carbon usually depends on handling.
  • Carbon is usually the major contaminant.  The amount of carbon ranges from 5-50 atom%.
  • Carbon contamination is attributed to air-borne organic gases that become trapped by the surface, oils transferred to the surface from packaging containers, static electricity, or handling of the product in the production environment.
  • Carbon contamination is normally a mixture of different chemical states of carbon (hydrocarbon, alcohol or ether, and ester or acid).
  • Hydrocarbon is the dominant form of carbon contamination. It is normally 2-4x larger than the other chemical states of carbon.
  • Carbonate peaks, if they appear, normally appear ~4.5 eV above the hydrocarbon C (1s) peak max BE.
  • Low levels of carbonate is common on many s that readily oxidize in the air.
  • High levels of carbonate appear on reactive oxides and various hydroxides.  This is due to reaction between the oxide and CO2 in the air.
  • Hydroxide contamination peak is due to the reaction with residual water in the lab air or the vacuum.
  • The O (1s) BE of the hydroxide (water) contamination normally appears 0.5 to 1.0 eV above the oxide peak
  • Sodium (Na), Potassium (K), Sulfur (S) and Chlorine (Cl) are common trace to low level contaminants
  • To find low level contaminants it is very useful to vertically expand the 0-600 eV region of the survey spectrum by 5-10X
  • A tiny peak that has 3 or more adjacent data-points above the average noise of the background is considerate to be a real peak
  • Carbides can appear after ion etching various reactive s.  Carbides form due to the residual CO and CH4 in the vacuum.
  • Ion etching can produce low oxidation states of the material being analyzed.  These are newly formed contaminants.
  • Ion etching polymers by using standard Ar+ ion guns will destroy the polymer, converting it into a graphitic type of carbon

→  Periodic Table 

 

Data Collection Guidance

 

  • Chemical state differentiation can be difficult
  • Collect principal Th (4f) peak
  • Long time exposures (high dose) to X-rays can degrade various polymers, catalysts, high oxidation state compounds
  • During XPS analysis, water or solvents can be lost due to high vacuum or irradiation with X-rays or Electron flood gun
  • Auger signals can sometimes be used to discern chemical state shifts when XPS shifts are very small

→  Periodic Table 

 

Data Collection Settings for Thorium (Th)

 

  • Conductivity:  Thorium is extremely fast to develop a native oxide that is sensitive to Flood Gun – Differential Charging Possible – float sample recommended
  • Primary Peak (XPS Signal) used to measure Chemical State Spectra:  Th (4f7/2) at 333 eV
  • Recommended Pass Energy for Measuring Chemical State Spectrum:  40-50 eV    (Produces Ag (3d5/2) FWHM ~0.7 eV)
  • Recommended # of Scans for Measuring Chemical State Spectrum:  4-5 scans normally   (Use 10-25 scans to improve S/N)
  • Dwell Time:  50 msec/point
  • Step Size:  0.1 eV/point   (0.1 eV/step or 0.1 eV/channel)
  • Standard BE Range for Measuring Chemical State Spectrum:  325-355eV
  • Recommended Extended BE Range for Measuring Chemical State Spectrum:  320-380 eV
  • Recommended BE Range for Survey Spectrum:  -10 to 1,100 eV   (above 1,100 eV there are no useful XPS signals, except for Ge and Ga)
  • Typical Time for Survey Spectrum:  3-5 minutes for newer instruments, 5-10 minutes for older instruments
  • Typical Time for a single Chemical State Spectrum with high S/N:  5-10 minutes for newer instruments, 10-15 minutes for older instruments 

→  Periodic Table 

 

Effects of Argon Ion Etching

 

  • Carbides appear after ion etching Th and various reactive surfaces.  Carbides form due to the presence of residual CO and CH4 in the vacuum.
  • Ion etching can produce low oxidation states of the material being analyzed.  These are newly formed contaminants.
  • Ion etching polymers by using standard Ar+ ion guns will destroy the polymer, converting it into a graphitic type of carbon

 

→  Periodic Table 

Copyright ©:  The XPS Library 
Gas Phase XPS or UPS Spectra

 

Chemical State Spectra from Literature
xxx

End of File