We describe a gas-phase x-ray scattering experiment capable of capturing molecular motions with atomic spatial resolution and femtosecond time resolution. X-ray free electron lasers can deliver intense x-ray pulses of ultrashort duration, making them suitable to study ultrafast chemical reaction dynamics in an ultraviolet pump, x-ray probe scheme. A cell diffractometer balances sample flow with...

The Coulomb explosion of the octamer water cluster has been studied employing time-dependent density functional theory explicitly accounting for the laser field and thus not imposing any constraint on the interaction between the laser pulse and the cluster. We focus on the effects of electron density changes in the system under high-intensity (10(16) and 10(15) W cm(-2)) soft X-ray laser pulses...

Diffuse x-ray scattering is a powerful means to study the structure of defects in crystalline solids. The traditional analysis of diffuse x-ray scattering experiments relies on analytical and numerical methods which are not well suited for studying complicated defect configurations. We present here an atomistic simulation method by which the diffuse x-ray scattering can be calculated for an arb...

Although x-ray imaging is widely used in biomedical applications, biological soft tissues have small density changes, leading to low contrast resolution for attenuation-based x-ray imaging. Over the past years, x-ray small-angle scattering was studied as a new contrast mechanism to enhance subtle structural variation within the soft tissue. In this paper, we present a detection method to extrac...

The imaging performance of X-ray optics (expressed in terms of HEW, HalfEnergy-Width) can be severely affected by X-ray scattering caused by the surface roughness of the mirrors. The impact of X-ray scattering has an increasing relevance for increasing photon energy, and can be the dominant problem in a hard X-ray telescope like SIMBOLX. In this work we show how, by means of a novel formalism, ...

1.59.1 PHYSICS OF X-RAY ABSORPTION 1 1.59.1.1 X-ray Absorption Edges 2 1.59.1.2 X-ray Fluorescence 3 1.59.1.3 Measurement of X-ray Absorption Spectra 3 1.59.2 EXTENDED X-RAY ABSORPTION FINE STRUCTURE 6 1.59.2.1 Theoretical Description of EXAFS Spectra 6 1.59.2.1.1 Single scattering 6 1.59.2.1.2 Multiple scattering 8 1.59.2.1.3 Other corrections to the EXAFS equation 9 1.59.2.2 Programs for Calc...

In this research program, modern x-ray scattering techniques are used to study the structures and phase transitions in novel states of condensed matter. We have two principal experimental facilities. At M.I.T. we have two high-resolution computer controlled x-ray spectrometers using a high intensity rotating anode x-ray generator. Two more spectrometers are currently under development. The angu...

In this research program, modern x-ray scattering techniques are used to study the structures and phase transitions in novel states of condensed matter. We have two principal experimental facilities. At M.I.T. we have three high-resolution computer controlled x-ray spectrometers using either a conventional or high intensity rotating anode x-ray generator. The angular resolution can be made as f...

(2013). X-ray scattering of a nematic liquid crystal nano-dispersion with negative dielectric anisotropy. A nematic liquid crystal (LC) mixture was doped with harvested ferroelectric BaTiO 3 nanoparticles and investigated with wide-and small-angle x-ray scattering upon heating from the nematic to the isotropic phase. At moderate temperatures, colloidal crystallites were observed. LC test cells ...

Diffuse X-ray scattering is a useful method for studying defects in silicon and metals. Although the traditional approaches of analyzing experimental diffuse X-ray scattering data have given much information about the size of defects and defect clusters, they are not very well suited for determining the atomic configuration. We present a fully atomistic computational method to calculate the dif...