LCLS Studies of Laser Initiated Dynamics Jorgen Larsson, David Reis, Thomas Tschentscher, and Kelly Gaffney provided LUSI management with preliminary Specifications on February 2, 2006 I have provided you with a print out of the specifications

Defining the Scope of Pump-Probe Endstation Is this where multi-shot imaging will be performed? Where will intense x-ray pump – x-ray probe experiments be performed? Will pulsed magnetic field experiments be performed here? Will all general scattering experiments be performed in this endstation? - Where will x-ray pump – x-ray probe experiments be conducted? - Will imaging experiments be conducted in this endstation? - Will pulsed magnetic field experiments be done here? - Will gas phase, cluster, and UHV/surface experiments be performed here? - Where will the soft x-ray pump probe experiments be conducted?

Core Capability for Pump-Probe Experiments Contained in the LOI X-ray scattering probes of sturctural dynamics in condensed phases - This will include diffuse scattering measurements of structure factors in the liquid phase - Diffuse scattering in crystals - Bragg and Laue scattering in crystals Hard x-ray emission spectroscopy -Initially focused on non-resonant XES - Extended to XANES and RIXS X-ray pump studies to be probed by x-rays or laser pulses

Beam Splitting Monochromator Asymmetric Bragg geometry will lead to temporal pulse broadening Cannot preserve full LCLS intensity – need to maintain direct beam capability - This presents the potential problem of needing to reproducibly move the table with a beam diameter precision Needs to cover a large energy range, including 3 rd harmonic -Ideally 4 keV to 20 keV, low range for XANES and high range for liquid scattering

LCLS Diagnostics LCLS Pulse synchronization diagnostics -Implementing electro-optic sampling from the beginning is essential - Developing x-ray laser pulse cross correlation methods needs to be integrated into the LCLS commissioning LCLS Pulse energy diagnostics - With beam splitting monochromator set-up, metal foil calibration should be sufficient -With direct beam studies the e - beam energy diagnostic has been proposed as a measure of the relative energy shot-to-shot LCLS Pulse energy diagnostics -This is essential for diffuse scattering experiments, either in solids or liquids, where the pump induced change will often be a small fraction of the total scatter - For liquids, normalizing to the solvent molecular structure factor at high-Q provides an alternative way of observing relative changes. This makes the 3 rd harmonic essential to these studies Optical Laser diagnostics - Online measures of pulse position, spectrum, energy, and duration will be important

Table rails for doing direct beam and displaced beam experiments. Motion needs to be high precision. x-ray slits x-ray BPM Dual crystal x-ray monochromator with large horizontal displacement for running in parallel with far hall and resolving power from 4 to 16 keV Ability to work with either the fundamental or the 3 rd harmonic 1.5 m Five-circle goniometer with 1 m diameter capable of accommodating liquid, crystal, and powder samples, and potentially a small vacuum chamber. Needs to be compatible with sample heating and cooling. Laser table: 4’X12’ Vacuum up to the x-ray slits X-ray table: 5’X15’ Room 9.5 X 10 m 2 Overhead view of laser pump x-ray probe hutch Monochromator and CCD array for simultaneous UV to near IR light probing of system dynamics Mono+CCD x-ray emission spectrometer

direct beam displaced, monochromatic beam 1.5 m ‘1-D detector’, though the x-ray detector I would work array of cylindrically bent analyzer crystals Side view of emission spectrometer set-up

Significance of Soft X-ray Probing of Laser Induced Dynamics Photoinduced charge transfer at interfaces critical to key DOE programs -Photovoltaics - Photoelectrochemical production of hydrogen Presents the opportunity to develop non-linear spectroscopy - surface selective probes of electronic structure and potentially surface chemistry -potential for x-ray laser cross correlation Photo-doped studies of carrier dynamics in correlated electron systems -Use L-edge spectroscopy for studying transient electronic structure in metal oxides

Ultrafast Charge Transfer in Photovoltaic Cell Schematic of cell time scale for carrier generation Asbury et al. J. Phys. Chem. B 104, 4545 (2001).Hagfeldt and Grätzel Acc. Chem. Res. 33, 269 (2000).

Phonon vs. Electron Driven Catalysis – Oxidation of CO on Ru(0001) Bonn et al. Science 285, 1042 (1999).

Photo-doping Studies of Metal Insulator Transition in VO 2 Cavalleri et al. Phys. Rev. Lett. 95, (2005) and Cavalleri et al. Phys. Rev. B 70, R (2004).