Simulation of Xe$_{n}$Ar$_{m}$ Cluster Formation in a Molecular Beam: Comparison with Photoelectron Spectroscopy

We perform direct MD simulations of the formation of mixed Xe$_{n}$Ar$_{m}$ clusters (500$<$n+m$<$3000) in a supersonic beam as a function of initial beam conditions. We then model the 4d$_{5/2}$ (Xe) and 2p$_{3/2} $ (Ar) core hole photoelectron spectra of these clusters and compare them to the experimental spectra of Tchaplyguine \textit{et al}[1]. The predicted spectra are calculated as the sum of final state energy shifts of the ionized atoms (within the cluster) relative to the isolated gas phase ion using a self-consistent polarization formalism. We use the results of our earlier calculations on pure argon and xenon clusters [2] to determine the appropriate inelastic mean free path value for the signal electrons leaving the mixed clusters. These results allow us to gain a refined understanding of the size, stoichiometry, and core/shell structure of these mixed clusters. [1] M. Tchaplyguine, \textit{et al}, Phys. Rev A \textbf{69}, 031201 (2004); [2] F. Amar, \textit{et al}, JCP \textbf{122}, 244717 (2005).