Line shape and lifetime in argon 2p electron spectroscopy

The argon 2p photoelectron spectrum and the argon L3M23M23 S-1(0) Auger spe ctrum have been measured at several photon energies between 6 and 80 eV abo ve the 2p(3/2) threshold with an instrumental line width significantly smal ler then the natural line width. The spectra are described well by the theo ry of van der Straten et al. [Z. Phys. D 8 (1988) 35] provided that allowan ce is made for the instrumental resolution and measurements are made at a s ufficiently low pressure. The lifetime (Lorentzian) line width determined f rom these measurements for the core-ionized atom is 112 +/-3 meV, in good a greement with the line width for the 2P(3/2) --> 4s core-excited state, 114 +/-2 meV indicating that the 4s electron has little influence on the Auger decay rate. Remeasurement of the line width for the carbon ls hole in carb on dioxide gives values in good agreement with the previous measurement of 99 meV. (C) 2001 Elsevier Science BY All rights reserved.