# FS-FLASH-D

 2018-10-1414:42 [PUBDB-2018-03783] Journal Article et al Photoionization of metastable heliumlike $C^{4+}$($1s\,2s\; ^3S_ 1)$ ions: Precision study of intermediate doubly excited states Physical review / A 98(3), 033416 (2018) [10.1103/PhysRevA.98.033416]   In a joint experimental and theoretical endeavor, photoionization of metastable $C^{4+}$($1s\,2s\; ^3S_ 1)$ ions via intermediate levels with hollow, double-K-vacancy configurations $2s2p, 2s3p, 2p3s, 2p3d, 2s4p, 2p4s$, and $2p4d$ has been investigated. High-resolution photon-ion merged-beams measurements were carried out with the resolving power reaching up to 25 800 which is sufficient to separate the leading fine-structure components of the $2s2p^{3}P$ term. [...] OpenAccess: PDF PDF (PDFA); 2018-09-2710:43 [PUBDB-2018-03641] Journal Article et al Probing the non-equilibrium transient state in magnetite by a jitter-free two-color X-ray pump and X-ray probe experiment Structural dynamics 5(5), 054501 (2018) [10.1063/1.5042847]   We present a general experimental concept for jitter-free pump and probe experiments at free electron lasers. By generating pump and probe pulse from one and the same X-ray pulse using an optical split-and-delay unit, we obtain a temporal resolution that is limited only by the X-ray pulse lengths. [...] OpenAccess: PDF PDF (PDFA); 2018-08-3010:18 [PUBDB-2018-03255] Journal Article et al XUV double-pulses with femtosecond to 650 ps separation from a multilayer-mirror-based split-and-delay unit at FLASH Journal of synchrotron radiation 25(5), 1517 - 1528 (2018) [10.1107/S1600577518006094]   Extreme ultraviolet (XUV) and X-ray free-electron lasers enable new scientific opportunities. Their ultra-intense coherent femtosecond pulses give unprecedented access to the structure of undepositable nanoscale objects and to transient states of highly excited matter [...] OpenAccess: PDF PDF (PDFA); 2018-08-2014:27 [PUBDB-2018-03069] Journal Article et al CAMP@FLASH: an end-station for imaging, electron- and ion-spectroscopy, and pump–probe experiments at the FLASH free-electron laser Journal of synchrotron radiation 25(5), 1529 - 1540 (2018) [10.1107/S1600577518008585]   The non-monochromatic beamline BL1 at the FLASH free-electron laser facility at DESY was upgraded with new transport and focusing optics, and a new permanent end-station, CAMP, was installed. This multi-purpose instrument is optimized for electron- and ion-spectroscopy, imaging and pump–probe experiments at free-electron lasers [...] OpenAccess: PDF PDF (PDFA); 2018-05-1415:17 [PUBDB-2018-01956] Journal Article et al Time-resolved inner-shell photoelectron spectroscopy: From a bound molecule to an isolated atom Physical review / A 97(4), 043429 (2018) [10.1103/PhysRevA.97.043429]   Due to its element and site specificity, inner-shell photoelectron spectroscopy is a widely used technique to probe the chemical structure of matter. Here, we show that time-resolved inner-shell photoelectron spectroscopy can be employed to observe ultrafast chemical reactions and the electronic response to the nuclear motion with high sensitivity. [...] Fulltext: PNG; OpenAccess: PDF PDF (PDFA); 2018-01-1715:59 [PUBDB-2018-00674] Journal Article et al Near-K -edge single, double, and triple photoionization of $C^{+}$ ions Physical review / A 97(1), 013409 (2018) [10.1103/PhysRevA.97.013409]   Single, double, and triple ionization of the $C^{+}$ ion by a single photon have been investigated in the energy range 286 to 326 eV around the K-shell single-ionization threshold at an unprecedented level of detail. At energy resolutions as low as 12 meV, corresponding to a resolving power of 24 000, natural linewidths of the most prominent resonances could be determined [...] OpenAccess: PDF PDF (PDFA); External link: Fulltext 2018-01-1113:18 [PUBDB-2018-00484] Journal Article et al Circular Dichroism in Multiphoton Ionization of Resonantly Excited $He^{+}$ Ions Physical review letters 118(1), 013002 (2017) [10.1103/PhysRevLett.118.013002]   Intense, circularly polarized extreme-ultraviolet and near-infrared (NIR) laser pulses are combined to double ionize atomic helium via the oriented intermediate He+(3p) resonance state. Applying angle-resolved electron spectroscopy, we find a large photon helicity dependence of the spectrum and the angular distribution of the electrons ejected from the resonance by NIR multiphoton absorption. [...] OpenAccess: PDF PDF (PDFA); 2018-01-0910:44 [PUBDB-2018-00272] Journal Article et al Ultrashort Free-Electron Laser X-ray Pulses Applied Sciences 7(9), 915 - (2017) [10.3390/app7090915]   For the investigation of processes happening on the time scale of the motion of bound electrons, well-controlled X-ray pulses with durations in the few-femtosecond and even sub-femtosecond range are a necessary prerequisite. Novel free-electron lasers sources provide these ultrashort, high-brightness X-ray pulses, but their unique aspects open up concomitant challenges for their characterization on a suitable time scale [...] OpenAccess: PDF PDF (PDFA); 2018-01-0815:32 [PUBDB-2018-00266] Journal Article et al Saturation of a Ce:$\mathrm{Y}_{3}\mathrm{Al}_{5}\mathrm{O}_{12}$ scintillator response to ultra-short pulses of extreme ultraviolet soft X-ray and X-ray laser radiation Optical materials express 7(3), 665 - 675 (2017) [10.1364/OME.7.000665]   Investigations of radioluminescence saturation in monocrystalline cerium doped yttrium aluminum garnet (Ce:YAG) exposed to intense extreme ultraviolet (XUV), soft X-ray and X-ray radiation delivered from three free-electron lasers are described in this article. The measurements were performed with wavelengths of 98, 25.6, 13.5 and 0.15 nm. [...] OpenAccess: PDF PDF (PDFA); 2018-01-0513:44 [PUBDB-2018-00199] Journal Article et al Photodissociation of Aligned $\mathrm{CH_3I}$ and $\mathrm{C_{6}H_{3}F_{2}I}$ Molecules Probed with Time-Resolved Coulomb Explosion Imaging by Site-Selective XUV Ionization Structural dynamics 5(1), 014301 - (2018) [10.1063/1.4998648]   We explore time-resolved Coulomb explosion induced by intense, extreme ultraviolet (XUV) femtosecond pulses from a free-electron laser as a method to image photo-induced molecular dynamics in two molecules, iodomethane and 2,6-difluoroiodobenzene. At an excitation wavelength of 267 nm, the dominant reaction pathway in both molecules is neutral dissociation via cleavage of the carbon–iodine bond. [...] Fulltext: PNG; OpenAccess: PDF PDF (PDFA);