Cao CaO CaCO3 Ca(SO4)  CaWO4 CaTiO3 CaTiSiO5 CaMg(CO3)2    CaI2  CaBr2  CaCl2  CaF2       Basic 

XPS Spectra
Calcium (Ca) Compounds
The XPS Spectra section provides raw and processed survey spectra, chemical state spectra, BE values, FWHM values, and overlays of key spectra.
Atom% values from surveys are based on sample, as received, and Scofield cross-sections. Atom% values are corrected for IMFP and PE.
Peak-fits are guides for practical, real-world applications. Peak-fits are not fully optimized or designed to test any theory.

Calcium Tungstate (CaWO4 – Scheelite)
Survey, Peak-fits, BEs, FWHMs, and Peak Labels

→  Periodic Table   → Six (6) BE Tables
Survey Spectrum from CaWO4
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag (3d5/2) FWHM = 1.3 eV
→  Periodic Table  → Six (6) BE Tables
Ca (2p) Spectrum from CaWO4 – Raw
Fresh exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV		 Ca (2p) Spectrum from CaWO4– Peak-Fit
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV

 
 
Ca (2p) Spectrum from CaWO4 – Extended Range
Fresh exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV		 Ca (2p) Spectrum from CaWO4 – Raw – Vertically Expanded
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
→  Periodic Table  → Six (6) BE Tables
O (1s) Spectrum from CaWO4 – Raw
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV		 O (1s) Spectrum from CaWO4 – Peak-fit
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
→  Periodic Table  → Six (6) BE Tables
O (1s) Spectrum from CaWO4 – Raw – Extended Range
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV		 O (1s) Spectrum from CaWO4 – Raw – Vertically Expanded
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
 
→  Periodic Table  → Six (6) BE Tables
C (1s) Spectrum from CaWO4 – Peak-fit – As measured 
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 284.71 eV, Ag FWHM = 0.75 eV		 C (1s) Spectrum from CaWO4 – Peak-Fit – Corrected
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
→  Periodic Table  → Six (6) BE Tables
W (4f) Spectrum from CaWO4 – Raw
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV		 W (4f) Spectrum from CaWO4 – Peak-Fit
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
 
W (4f) Extended W (4f) Expanded

→  Periodic Table  → Six (6) BE Tables
O (KLL) Auger Spectrum from CaWO4 – Raw
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV		 Valence Band Signals from CaWO4 – Raw
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
 
Overlays
→  Periodic Table  → Six (6) BE Tables
Valence Band Spectra – Overlay of CaO and CaWO4
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV		 Ca (2p) Spectra – Overlay of Cao and CaWO4
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV
→  Periodic Table  → Six (6) BE Tables
Ca (2p) Spectra – Overlay of CaO and CaWO4
Freshly exposed bulk, Flood gun is ON, C (1s) BE = 285.0 eV, Ag FWHM = 0.75 eV

End-of-spectra

Price to purchase raw data sets:
Raw spectra – VAMAS ASCII format ($6)
Raw spectra – SDP binary format ($5)
SDP v9 – $145 (3 yr license)

 

 

 

Transmission Function Tests
 

December 2015 – Transmission Function of Thermo K-Alpha Plus
→  Periodic Table 
Survey Spectra of Ion Etched Copper (Cr), PEs = 50, 100, 150 and 200 eV
→  Periodic Table 
March 2016 – Transmission Function of Thermo K-Alpha Plus 
 
Survey Spectra of Ion Etched Copper (Cr), PEs = 100, 150 and 200 eV
→  Periodic Table  
August 2019 – Transmission Function of Thermo K-Alpha Plus
 
Survey Spectra of HOPG (C), PEs = 20, 50, 100 and 200 eV
→  Periodic Table  
January 2022 – Transmission Function of Thermo K-Alpha Plus
Survey Spectra of Ion Etched Copper (Cr), PEs = 100, 120, 140, 160, 180 and 200 eV

 

Six (6) Chemical State Tables of Ca (2p) 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
  • There are uncertainties and error ranges in nearly all BEs 
    • Flood guns
  • 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

Ca (2p) 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 NIST BE Hydrocarbon C (1s) BE  Source
Ca 20 Ca – element (N*1) 345.9 eV 284.8 eV Avg BE – NIST
Ca 20 Ca – element 346.3 eV 285.0 eV The XPS Library
Ca 20 Ca-TiO3 346.3 eV 285.0 eV The XPS Library
Ca 20 Ca-CO3 346.4 eV 285.0 eV The XPS Library
Ca 20 Ca-(OH)2 (N*1) 346.7 eV  284.8 eV Avg BE – NIST
Ca 20 Ca-CO3 (N*4) 346.7 eV 347.0 eV  284.8 eV Avg BE – NIST
Ca 20 Ca-O 347.1 eV 285.0 eV The XPS Library
Ca 20 Ca-WO4 347.2 eV 285.0 eV The XPS Library
Ca 20 Ca-Mg(CO3)2 347.8eV 285.0 eV The XPS Library
Ca 20 Ca-F2 (N*2) 347.8 eV 347.9 eV  284.8 eV Avg BE – NIST
Ca 20 Ca-F2 348.0 eV 348.3 eV 285.0 eV The XPS Library
Ca 20 Ca-SO4 348.1 eV 285.0 eV The XPS Library
Ca 20 Ca-Cl2 348.2 eV 285.0 eV The XPS Library
Ca 20 Ca-Br2 348.2 eV 285.0 eV The XPS Library
Ca 20 Ca-I2 348.3 eV 285.0 eV The XPS Library

Charge Referencing

  • (N*number) identifies the number of NIST BEs that were averaged to produce the BE in the middle column.
  • Binding Energy Scale Calibration expects 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 (SO) 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

Ca (2p) Chemical State BEs from:  “PHI Handbook”

C (1s) BE = 284.8 eV

Copyright ©:  Ulvac-PHI

Table #3

Ca (2p) Chemical State BEs from:  “Thermo-Scientific” Website

C (1s) BE = 284.8 eV

Chemical state Binding energy,  Ca 2p (eV)
CaCO3 347.2
Ca3(PO4)2 347.4

→  Periodic Table 

Copyright ©:  Thermo Scientific website

Table #4

Ca (2p) 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

 

Copyright ©:  Mark Beisinger

Table #5

Ca (2p) Chemical State BEs from:  “Techdb.podzone.net” Website

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

Element Level Compound B.E.(eV) min max
Ca 2p3/2 CaCrO4 346.3 ±0.3 346.0 ～ 346.6
Ca 2p3/2 Ca 346.4 ±0.5 345.9 ～ 346.9
Ca 2p3/2 CaS 346.5 ±0.3 346.2 ～ 346.8
Ca 2p3/2 CaO 346.5 ±0.4 346.1 ～ 346.9
Ca 2p3/2 CaCO3 346.9 ±0.4 346.5 ～ 347.3
Ca 2p3/2 Ca3Si3O9 347.0 ±0.3 346.7 ～ 347.3
Ca 2p3/2 CaMoO4 347.2 ±0.3 346.9 ～ 347.5
Ca 2p3/2 CaF2 347.8 ±0.3 347.5 ～ 348.1
Ca 2p3/2 CaSO4 348.0 ±0.3 347.7 ～ 348.3
Ca 2p3/2 CaCl2 348.3 ±0.4 347.9 ～ 348.6
Ca 2p3/2 Ca(NO3)2 348.7 ±0.3 348.4 ～ 349.0

 

Histograms of NIST BEs from Ca (2p)
NIST Database defines Adventitious Hydrocarbon C (1s) BE = 284.8 eV for all insulators.

Histogram indicates Ca (2p) BE = 346.5 eV for Calcium Oxide (CaO)
based on 5 literature BEs		 Histogram indicates Ca (2p) BE = 346.9 eV for Calcium Carbonate (CaCO3)
 based on 4literature BEs

Table #6

NIST Database of Ca (2p) Binding Energies

NIST Standard Reference Database 20, Version 4.1

Data compiled and evaluated
by
Caexander 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. Cal rights reserved.