Nonlinear Atomic Response to Intense Ultrashort X Rays

Ultrafast Dynamics of a Nucleobase Analogue Illuminated by a Short Intense X-ray Free Electron Laser Pulse

“…The cascading processes of creating low-energy electrons and ionic radicals, which play a crucial role in the damage, are also of current fundamental interest [22,23]. XFEL pulses, which are the subject of the present work, are known to cause, even for isolated atoms, major changes in electronic structure via multiphoton absorption followed by Auger processes [24][25][26][27]. At the other end of the scale, in condensed matter and clusters of 10 3 -10 5 atoms, the intense XFEL pulses produce a dense nanoplasma, in which the dynamics of electrons and ions are strongly correlated with each other [28,29].…”

Multiple ionization and fragmentation dynamics of molecular iodine studied in IR–XUV pump–probe experiments

“…This is shown in Fig. 7, where the delay-dependent KER spectra are plotted for the coincidence channels (1,3) and (1,4). From this we draw the conclusion that delayed ionization by the IR laser favours the production of symmetric charge-state distributions.…”

“…The precursors with a neutral fragment are assigned as above. The charged precursors are identied using the Coulomb explosion model to be (1,2) and (1, 1) For a preceding XUV pulse the spectra are analyzed in exactly the same way, but neutral precursors can be neglected. The delay-dependent part of the nal channel (1, 2) for instance is reached by producing the precursor (1, 1) and subsequent removal of a further electron by the IR probe.…”

“…Under these conditions atoms are ionized by multi-photon transitions, and charge states are reached that are inaccessible by single-photon absorption. 1,2 Moreover, atomic resonances were found to further enhance the efficiency of high charge-state production in heavy atoms. 3,4 In contrast to the atomic case, experiments with rare-gas clusters yielded a more subtle picture.…”

Atomistic three-dimensional coherent x-ray imaging of nonbiological systems

“…Unprecedented focused intensities at ultrashort wavelengths have led to the discovery of xray phemonena such as nonlinear multiphoton absorption in atoms, molecules, and clusters [6][7][8][9][10], atomic x-ray lasing [11,12], induced transparency or saturable absorption [6,9,10,[13][14][15], stimulated emission [16][17][18], and second harmonic generation [19]. Understanding these fundamental processes underpins the use of ultraintense XFEL pulses and fuels the dream of 3D imaging of single biomolecules using the "diffract-before-destroy" method initially envisioned at the dawn of the XFEL-enabled era of x-ray science [20,21].…”