Mixed ab initio quantum mechanical and Monte Carlo calculations of secondary emission from SiO2 nanoclusters

TL;DR

This paper introduces a combined quantum mechanical and Monte Carlo approach to accurately simulate Auger spectra from SiO2 nanoclusters, effectively matching experimental data without background subtraction.

Contribution

It presents a novel two-step method integrating ab initio calculations with Monte Carlo simulations to model Auger spectra directly from nanoclusters.

Findings

Accurately reproduces experimental spectra for SiO2

Effectively models inelastic energy losses in spectra

Provides a direct comparison to experimental data

Abstract

A mixed quantum mechanical and Monte Carlo method for calculating Auger spectra from nanoclusters is presented. The approach, based on a cluster method, consists of two steps. Ab initio quantum mechanical calculations are first performed to obtain accurate energy and probability distributions of the generated Auger electrons. In a second step, using the calculated line shape as electron source, the Monte Carlo method is used to simulate the effect of inelastic losses on the original Auger line shape. The resulting spectrum can be directly compared to 'as-acquired' experimental spectra, thus avoiding background subtraction or deconvolution procedures. As a case study, the O K-LL spectrum from solid SiO2 is considered. Spectra computed before or after the electron has traveled through the solid, i.e., unaffected or affected by extrinsic energy losses, are compared to the pertinent experimental spectra measured within our group. Both transition energies and relative intensities are well reproduced.