Studying Shocked Material Dynamics with Ultrafast X-rays

Ultrafast electron dynamics excited and probed with X-rays

The Grüneisen parameter determines the magnitude of the system dimensional change in response to its thermal energy variation. Differentiating the various contributions to the Grüneisen parameter is of great importance to clearly understand the thermal expansion mechanism of solids. In particular, the electronic Grüneisen parameter (γe) characterizes the electronic contribution to the thermal e...

Laser-Assisted Dynamics on Metallic Surfaces using Ultrafast X-Rays

Enhanced nonlinear response of Ne8+ to intense ultrafast x rays

We investigate the possible reasons for the discrepancy between the theoretical two-photon ionization cross section, ∼10−56 cm4 s, of Ne8+ obtained within the perturbative nonrelativistic framework for monochromatic light [S. Novikov and A. Hopersky, J. Phys. B 34, 4857 (2001)] and the experimental value, 7 × 10−54 cm4 s, reported in [G. Doumy et al., Phys. Rev. Lett. 106, 083002 (2011)] at a p...

Ultrafast X - ray Studies of Structural Dynamics

C20 of molecular structures for C70Br10 or C60Cl24, which have been later confirmed by X-ray crystallography (partially with the use of synchrotron radiation). For the mixture of two compounds with known X-ray structures, C60Cl28 and C60Cl30, the experimental IR spectra were interpreted by comparison with the calculated ones using subtle differences for compounds possessing very similar structu...

Ultrafast electron dynamics in the charge density wave material TbTe3

Gaining insights into the mechanisms of how order and broken symmetry emerges from many-particle interactions is a major challenge in solid state physics. Most experimental techniques—such as angle-resolved photoemission spectroscopy (ARPES)—probe the single-particle excitation spectrum and extract information about the ordering mechanism and collective effects, often indirectly through theory....