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Computer Modelling and Simulation of the Interaction of keV Clusters with Molecular Solids.

Mody, Jaydeep. (2012) Computer Modelling and Simulation of the Interaction of keV Clusters with Molecular Solids. Doctoral thesis, University of Surrey (United Kingdom)..

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Abstract

There is an increasing demand for techniques that are able to provide high resolution molecular imaging of biological materials. Secondary Ion Mass Spectrometry (SIMS) is one technique that has been focused on in order to achieve the above. Traditionally, SIMS has predominantly made use of atomic projectiles for this bombardment process - Atomic SIMS. However, a bit over two decades ago, a breakthrough in SIMS occurred with the advent of cluster projectiles - Cluster SIMS. This has generated deep interest for studying the nature of cluster-surface interactions. Ion-surface interactions have constantly had access to simulation programs with predictive capability. For cluster-surface interactions however, there is no such software available (yet). Some existing techniques are too slow for making predictions. Thus, the purpose of this thesis was to develop a model that was able to help in predicting SIMS relevant information for these cluster-surface interactions. The model used in the thesis is based on a simplistic energy spread approach that behaves according to a diffusional process. With the help of MD simulations, it is shown that the above approach can be a valid method for consolidating prediction capabilities for cluster-surface interactions. It has been shown that by dumping energy into the target and allowing this energy to spread, the dimension of the crater that is formed from a cluster impact can be emulated. In addition, the amount of material removed from the solid can also be matched. It was found that the following are key initial criteria that have to be met for the deposited energy. The angular distribution of the initially energetic particles is needed to be randomly and spherically distributed. The energy density (or temperature) is not required to be very sensitive although above a certain threshold. The energy requires to be deposited in such as way that its spread in the vertical direction is twice that in the lateral dimensions.

Item Type: Thesis (Doctoral)
Divisions : Theses
Authors : Mody, Jaydeep.
Date : 2012
Additional Information : Thesis (Ph.D.)--University of Surrey (United Kingdom), 2012.
Depositing User : EPrints Services
Date Deposited : 06 May 2020 14:07
Last Modified : 06 May 2020 14:12
URI: http://epubs.surrey.ac.uk/id/eprint/856036

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