ELASTIC-SCATTERING CORRECTIONS IN AES AND XPS .1. 2 RAPID MONTE-CARLOMETHODS FOR CALCULATING THE DEPTH DISTRIBUTION FUNCTION

We present improvements to the Monte Carlo methods used to calculate e mission depth distribution functions (DDFs), emission function decay l engths (EFDLs) and attenuation lengths in quantitative XPS and AES. Th ese reduce the time required to reach any desired level of accuracy by a factor Of approximately 500, so that even a personal computer can p roduce accurate results in 2 or 3 min. These rapid results are due to the new technique of averaging over an ensemble of possible inelastic events for each feasible set of elastic scatterings in the Monte Carlo simulation, closely related to methods that have been used successful ly in nuclear physics for many years. No new approximations are requir ed. The results are compared with exact analytical solutions for simpl e special cases; agreement is excellent.