Comparing Peak Asymmetries in EXAFS using RMC and Cumulant Expansion Data Analysis

EXAFS measurements on RbBr at the Br absorption edge and different temperatures were carried out. Conventional analysis of the data using the Daresbury EXCURV92 code shows with increasing temperature a decrease in nearest neighbour distance. Also large differences are found in the coordination numbers for k and k' weighted EXAFS with increasing temperature. Using cumulant expansion when fitting the data results in a small increase in nearest neighbour distance with temperature, as expected from thermal data.