Ab initio simulations of electronic spectra i liquids and dynamics in excited states
Person photo Dr Michael Odelius
Department of Physics


Svenska sammanfattning

Hur bryts en kemisk binding? Vad händer i vanligt vatten på en mikroskopisk nivå? Mycket av vår grundläggande förståelse av kemiska reaktioner och växelverkan mellan molekyler baseras på teoretiska metoder. Men realismen i dessa modeller måste ständigt frågasättas. Därför är kopplingen till experiment avgörande för trovärdigheten av de teoretiska resultaten. De teoretiska studierna sker i mycket nära samarbete med experimentella grupper, som representerar spektroskopiska metoder som kan ge väldigt detaljerade information on kemisk binding, molekylär struktur och reaktionsdynamik.

English summary

Ab initio molecular dynamics (MD) and spectrum simulations are performed for the interpretation of x-ray, optical, electron and vibrational spectroscopies with a focus on dynamical effects. Simulations relating to recent and future experiments on ultra-fast processes with x-ray spectroscopy give insight into processes studies with unprecedented time resolutions. A continuous interplay between theory and experiment acts as a stimulus for the method development.

English article

Molecular liquid and electrolytes are complex disordered systems best treated with statistical mechanics. Ab initio molecular dynamics is used to simulate aqueous solutions, alcohols and organic liquids. From the simulations we can model x-ray emission spectra which contain information on electronic structure and excited-state molecular dynamics and molecular interactions. 

Simulations are performed to model static x-ray spectra and time-resolved 2D-infra-red correlation spectroscopy on aqueous solutions, in which the electronic information is essential. Time-resolved photo-emission spectroscopy allows us to resolve the electronic changes during bond breaking and ultra-fast reactions. Time-resolved soft x-ray spectroscopy is beginning to produce results on the element-specific projection of the electronic structure, and time-resolved hard x-ray spectra give direct access to the nuclear motion in these processes. By studying the same system with different spectroscopic techniques the theoretical simulations can act as a common denominator in the combined theoretical and experimental effort.

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Hydrogen reorganisation occur in jumps