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Identifier

000286844

Title

Ανάπτυξη πειραματικής μεθόδου για την μελέτη της δομής και της δυναμικής μορίων και κρυστάλλων με την τεχνική σκέδασης κάθετων μοριακών δεσμών

Alternative Title

Structural and dynamics studies of small molecules and clusters via crossed beam scattering experiments

Author

Μασαούτη, Μαρία

Thesis advisor

Φαράντος, Σταύρος

Abstract

In order to perform in a more sophisticated manner, structural and dynamics studies of free clusters and molecules, a new experimental method was developed, based on the well known crossed-beam scattering technique combined with modern imaging technologies. This novel method facilitates measurements of differential collision cross-sections and double differential cross-sections and therefore gives valuable information on the dynamics of the colliding species and their structure. The investigation of simple collision systems (Ta+-Ne, N2, CO, C2H2) with this method were performed in the non-adiabatic regime (impulsive collisions) which is a not yet extensively explored region and where the colliding species can be treated as hard bodies. The measurements of the angular dependence of the differential crosssection reveal that the potential energy, which governs the ion-atom interaction, in the specific energy regime, exhibits a Coulombic repulsive behavior of the empirical Universal form. Moreover, the energy loss spectra recorded in ion-molecule collisions, indicate that energy is transferred both in rotational and vibrational degrees of freedom of the molecules. The simple hard-potential model was employed in the theoretical analysis of this inelastic process. By means of this model, we determined the equipotential surface, which characterize the interaction of the colliding species and subsequently the structure of the molecule in the specific collision energy. This novel experimental technique in conjunction with simple theoretical models is a promising new tool for static (structure) and dynamics (fragmentation, energy transfer, reactivity, etc.) studies of gas-phase molecules and clusters.

Language

Greek

Subject

Differetial cross-section clusters

Moleculaer beams

Διαφορική ενεργός διατομή

Μοριακές δέσμες

Issue date

2006-09-29

Collection

School/Department--School of Sciences and Engineering--Department of Chemistry--Doctoral theses

Type of Work--Doctoral theses