Natural FWHM


Natural FWHM of Element (spin-orbit) ???



Total FWHM = (FWHMx-ray2 + FWHMhemi-sphere broadening2 + FWHMelement2 )1/2

Energy (Wavelength) Spreads




FWHMx-ray spread                                          0.16 – 0.21 eV 

FWHM (Lorentzian)




Shape of X-ray Energy Distribution ( λ)  is 100% Lorentzian



Shape of Emitted Photo-Electron Energy Distribution is 100% Lorentzian

(?? eV)



Energy Spread (Distribution) due to Electron Energy Analyzer is 0.25 eV   (100% Gaussian)


FWHMhemi-sphere broadening <0.25eV


Characterisation of the VG ESCALAB 220i-XL instrumental broadening functions by XPS measurements at the Fermi edge of silver

Image result for fermi edge



Natural FWHM of Ar 3p in gaseous state – UPS spectrum – not corrected for HSA or Source Spread

Natural FWHM of Aluminum Al 2p using Synchrotron Radiation not corrected for HSA spread or X-ray spread