TY  - THES
AU  - Anielski, Denis
TI  - Untersuchung der Photoelektronen-Winkelverteilungen von ausgerichteten Molekülen in der Gasphase
IS  - DESY-THESIS-2020-018
PB  - Universität Hamburg
VL  - Dissertation
CY  - Hamburg
M1  - PUBDB-2020-02797
M1  - DESY-THESIS-2020-018
T2  - DESY-THESIS
SP  - 206
PY  - 2020
N1  - Dissertation, Universität Hamburg, 2020
AB  - This work investigates if and how photoelectron diffraction might become a suitable tool to measure structural changes of small molecules in the gas-phase with femtosecond temporal and angstrom spatial resolution. Molecular-frame photoelectron angular distributions (MFPAD) of O(1s)-, S(2p)- and F(1s)-electrons from carbonyl sulfide and fluoromethane molecules have been measured in photoelectron-photoion coincidence experiments at the synchrotron radiation sources DORIS and PETRA III (kinetic energy of photoelectrons: 16 eV < E<sub>PE</sub> < 283 eV). It has been investigated which degree of molecular orientation is necessary to observe a rich structure in the MFPADs, which influence linearly and circularly polarized photons have on MFPADs, and if MFPADs of photoelectrons with a few 100 eV kinetic energy can be described by a simple scattering model.The relation of the measured MFPADs to the molecular structure was examined by MSXα calculations. At the free-electron laser FLASH, S(2p)-photoelectron angular distributions of adiabatically laser-aligned OCS molecules have been measured (E<sub>PE</sub>=44 eV). In an IR-pump-XUV-probe experiment at FLASH, molecular dynamics have been observed in the photoelectron angular distributions with femtosecond temporal resolution. The influence of the alignment and the pump laser on molecules and on photoelectrons has been discussed. This work indicates avenues how to reach the goal of observing ultrafast molecular structural changes by photoelectron diffraction.
LB  - PUB:(DE-HGF)3 ; PUB:(DE-HGF)11
DO  - DOI:10.3204/PUBDB-2020-02797
UR  - https://bib-pubdb1.desy.de/record/441908
ER  -