Show simple item record

dc.contributor.advisorMorrison, Caroleen
dc.contributor.advisorKirrander, Adamen
dc.contributor.authorMoreno Carrascosa, Andrésen
dc.date.accessioned2018-07-26T09:10:19Z
dc.date.available2018-07-26T09:10:19Z
dc.date.issued2018-11-29
dc.identifier.urihttp://hdl.handle.net/1842/31442
dc.description.abstractX-rays have been widely exploited to unravel the structure of matter since their discovery in 1895. Nowadays, with the emergence of new X-ray sources with higher intensity and very short pulse duration, notably X-ray Free Electron Lasers, the number of experiments that may be considered in the X-ray regime has increased dramatically, making the characterization of gas phase atoms and molecules in space and time possible. This thesis explores in the theoretical analysis and calculation of X-ray scattering atoms and molecules, far beyond the independent atom model. Amethod to calculate inelastic X-ray scattering from atoms and molecules is presented. The method utilizes electronic wavefunctions calculated using ab-initio electronic structure methods. Wavefunctions expressed in Gaussian type orbitals allow for efficient calculations based on analytical Fourier transforms of the electron density and overlap integrals. The method is validated by extensive calculations of inelastic cross-sections in H, He+, He, Ne, C, Na and N2. The calculated cross-sections are compared to cross-sections from inelastic X-ray scattering experiments, electron energy-loss spectroscopy, and theoretical reference values. We then begin to account for the effect of nuclear motion, in the first instance by predicting elastic X-ray scattering from state-selected molecules. We find strong signatures corresponding to the specific vibrational and rotational state of (polyatomic) molecules. The ultimate goal of this thesis is to study atomic and molecular wavepackets using time-resolved X-ray scattering. We present a theoretical framework based on quantum electrodynamics and explore various elastic and inelastic limits of the scattering expressions. We then explore X-ray scattering from electronic wavepackets, following on from work by other groups, and finally examine the time-resolved X-ray scattering from non-adiabatic electronic-nuclear wavepackets in the H2 molecule, demonstrating the importance of accounting for the inelastic effects.en
dc.language.isoen
dc.publisherThe University of Edinburghen
dc.relation.hasversionT. Northey et al. J. Chem. Phys. 145. Elastic X-ray scattering from stateselected molecules, 154304 (2016)en
dc.relation.hasversionA. M. Carrascosa, T. Northey, and A. Kirrander. Phys. Chem. Chem. Phys. 19. Imaging rotations and vibrations in polyatomic molecules with X-ray scattering, 7853 (2017)en
dc.relation.hasversionA. Moreno Carrascosa and A. Kirrander. Phys. Chem. Chem. Phys. 19. Ab initio calculation of inelastic scattering, 19545 (30 2017)en
dc.subjectX-ray scatteringen
dc.subjectdiffractionen
dc.subjectFree-Electron Lasersen
dc.subjectscattering patternsen
dc.subjectinelastic X-ray scatteringen
dc.subjectmolecular wavepacketsen
dc.subjectelectronic structureen
dc.subjectdynamicsen
dc.titleTheory of elastic and inelastic X-ray scatteringen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


Files in this item

This item appears in the following Collection(s)

Show simple item record