[MOS] Nov 2, Christoph Rose-Petruck, Brown University

[Vinnie Russo]

Dear Colleagues,

The G.R. Harrison Spectroscopy Laboratory and the Department of Electrical 
Engineering and Computer Science would like to invite you to the next 
seminar in our series on Modern Optics and Spectroscopy.

Date & Time:            Tuesday, November 2, 12 noon - 1 PM
Location:               Grier Room (34-401)
Speaker:                Christoph Rose-Petruck, Brown University
Title:                  Ultravast (XAFS) measurement of solvated transition 
metal complexes

Refreshments will be served following the talk.

Abstract
Christoph Rose-Petruck, Brown University
Ultravast (XAFS) measurement of solvated transition metal complexes
      Ultrafast high-intensity laser pulses incident upon condensed matter 
targets can generate high-density plasmas that emit x-ray pulses with 
sub-picosecond temporal structure, significant spatial coherence, and high 
brightness. Such a laser-driven plasma x-ray source operating at kilohertz 
repetition rates has been developed in our laboratory. Details of the 
experimental apparatus, including the x-ray optics are presented. Essential 
performance features related to ultrafast time-resolved x-ray absorption 
fine structure (XAFS) spectroscopy are discussed.
      Structural parameters of solvated Fe(CO)5 were measured by XAFS 
spectroscopy using our ultrafast laser driven x-ray source. The spectra are 
compared to XAFS spectra measured with a micro-focus as well as a 
synchrotron x-ray source. Furthermore, the data are compared to theoretical 
XAFS spectra based on Density Functional Theory (DFT) calculations of the 
solvated complex. All experimental and theoretical structure data were 
found to be in close agreement.
      Laser-pump XAFS-probe measurements of Fe(CO)64- in water have been 
performed at various pump-probe delay times before and after 
UV-photoexcitation of the complex. The experimental results are discussed 
and measured picosecond time-resolved XAFS spectra are presented.



Vinnie Russo * vrusso at mit.edu  *  Office Manager
MIT; G.R. Harrison  Spectroscopy Laboratory
77 Mass. Ave., 6-014  *  Cambridge, MA  02139
(v) 617-253-9774  *  (f) 617-253-4513 
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