Simulation of Electron Spectra for Surface

Recent calculations of Lave from MC simulations for Hf02 showed differences of up to 10% with values obtained from SRD 82 for film thicknesses less than 1 IMFP [94]. The MC simulations were made with the NIST Database for the Simulation of Electron Spectra for Surface Analysis (SESSA) described in more detail below [95]. The EAL differences arise from the fact that the EAL algorithm in SRD 82 is based on the simplifying assumption that material properties in a substrate/overlayer system do not depend on depth. This assumption is not made in SESSA, and it is therefore expected that EALs from SESSA wiU be more reliable than those from SRD 82 for substrate and overlayer materials that have different elastic- and inelastic-scattering properties. 

NIST Database for the Simulation of Electron Spectra for Surface Analysis (SRD 100) [95]. 

Figure 11. SNOM and LELS. a) schematic SNOM experiment b) spectra following transmission enhancement via surface plasmon excitations, from [39] Copyright 1998 by the American Physical Society c) LELS simulation of a similar experiment for a fast (100 kV) electron.

The most basic information that is needed for constructing a global potential energy surface for gas phase MD simulations is the structures and vibrational frequencies. The earliest information about gas-phase RDX molecular structures was obtained from theoretical calculations [54-58]. In 1984 Karpowicz and Brill [59] reported Fourier transform infrared spectra for vapor-phase (and for the a - and p -phase) RDX in 1984, however, their data precluded a complete description of the molecular conformations and vibrational spectroscopy. More recently, Shishkov et al. [60] presented a more complete description based on electron-scattering data and molecular modeling. They concluded that the data were best reproduced by RDX in the chair conformation with all the nitro groups in axial positions. 

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