First steps towards probing chemical systems and dynamics with free-electron laser radiation-–case studies at the FLASH facility

Abstract

It is expected that free-electron laser (FEL) radiation with its unique properties will allow real-time tracking of structural changes during chemical reactions. The methods suggested being applied range from x-ray spectroscopy to diffraction. In order to reach this goal, in this work we will present our studies utilizing soft x-ray FEL radiation generated at the FLASH facility. We will present case studies of ultrafast x-ray diffraction on nanocrystalline lamellar assemblies of chemical relevance and heat dissipation studies on polymer foils (upon FLASH excitation) as revealed by ultrafast optical reflectivity. The extension of these studies to characterize in vacuum water jets during their interaction with FEL radiation will be given at the end if this overview. In conclusion, it can be stated that FLASH-FEL radiation can be used for studying chemical processes as long as the pulse duration is smaller than the characteristic time scales of destruction (ionization) and heat dissipation processes.

Jitter-correction for IR/UV-XUV pump-probe experiments at the FLASH free-electron laser

“…, clusters and nanoparticles (Krikunova et al 2012a, 2012b, Clark et al 2015, Ferguson et al 2016, Flückiger et al 2016, Gorkhover et al 2016, liquids (Hallmann et al 2010, Wernet et al 2015, Biasin et al 2016, solids (Rajkovic et al 2010, Dell'Angela et al 2013, Siefermann et al 2014, Gleason et al 2015, Öström et al 2015, Rettig et al 2016, and even biological systems such as photoactive proteins (Aquila et al 2012, Tenboer et al 2014, Barends et al 2015, Pande et al 2016. Many of these time-resolved experiments require precise synchronization of an optical femtosecond laser with the FEL.…”

Development of Ultrafast X-ray Free Electron Laser Tools in (Bio)Chemical Research

“…The current examples emphasize, however, that the real world, functional materials, pharmaceuticals, catalysts or energy converting materials are not always crystalline and far from being periodically ideally arranged as it could look like when performing model type of investigations. If the intrinsic spatial resolution of the system does not allow for such detailed investigations, a combination of ultrafast X-ray spectroscopy and ultrafast X-ray diffraction or scattering as the "local to global approach" deliver configuration and charge information of the molecules studied [60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76]. This approach will be described in the following chapter.…”

“…As ultrafast X-ray spectroscopy and X-ray diffraction can "shake their hands" in Xray Free-electron laser science, they open up new ways to study complex chemical reactions. X-ray diffraction [17-59] and X-ray spectroscopy [60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76] are complementary techniques. X-ray spectroscopy allows probing the electronic properties in an element-, orbital-and site-specific way, for example bonding or oxidation state changes [63].…”

“…The first example is a time-resolved X-ray diffraction measurement on silverbehenate [60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76] with an outlook towards combination of the liquid jet with X-ray spectroscopy, the second example is a femtosecond time-resolved X-ray spectroscopy experiment on iron-pentacarbonyl (Fe(CO) 5 ) [78][79][80][81]. Figure 17.10a shows the apparatus which has been developed for such experiments at FELs.…”

“…Starting from this introduction as a comprehensive summary of the basic principles, in the following, various FEL methods developed so far will be summarised, including the concept of filming chemical reactions in real time utilizing ultrafast high-flux X-ray sources [11][12][13][14][15][16], X-ray Diffraction and Crystallography for Condensed State Chemistry Studies-Crystallography with Ultrahigh Temporal and Ultrahigh Spatial Resolution [14, and Applications in organic electronics and energy research [14,[53][54][55][56][57][58][59]; from From Local to Global: Ultrafast Multidimensional Soft X-ray Spectroscopy and Ultrafast X-ray Diffraction Shake Their Hands [60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76] and Applications in Bimolecular Reaction Studies and Photocatalysis [77][78][79][80] to Applications in Unimolecular Liquid Phase Reaction Dynamics [81][82][83][84][85][86][87][88]…”