Ultrafast X-ray absorption near edge spectroscopy has been carried out for photo excited iron pentacarbonyl in ethanol with 2 picosecond resolution. A temporal resolution limited dissociation process was observed, followed by the formation of the mono-substituted complex Fe(CO)(4)EtOH within a few tens of picoseconds. The measurements have been carried out with a newly developed X-ray absorption instrument at station 7 ID-C of the Advanced Photon Source. The results show that single picosecond temporal resolution can be achieved at a synchrotron beam line.

Photofragment spectra of jet-cooled MCH2 + (M = Fe, Co, Ni) have been measured. Our investigation of NiCH2 + represents the first reported spectroscopic study of this molecule. A spectroscopic threshold is observed for each of the three systems. In addition to imposing strict upper limits on the M+−CH2 bond strengths, these results further the discussion concerning the interpretation of spectroscopic thresholds as thermodynamic limits. The measured upper limits are:  D°0(Fe+−CH2) ≤ 342 ± 2 kJ/mol, D°0(Co+−CH2) ≤ 331 ± 2 kJ/mol, and D°0(Ni+−CH2) ≤ 295 ± 5 kJ/mol. Three distinct, 2-nm-wide peaks are observed in the photofragment spectrum of CoCH2 +, but the spectra lack sharp structure above threshold.

We report a new preparative method for providing contrast through reduction in electron density that is uniquely suited for propagation-based differential x-ray phase contrast imaging. The method, which results in an air or fluid filled vasculature, makes possible visualization of the smallest microvessels, roughly down to 15 microm, in an excised murine liver, while preserving the tissue for subsequent histological workup. We show the utility of spatial frequency filtering for increasing the visibility of minute features characteristic of phase contrast imaging, and the capability of tomographic reconstruction to reveal microvessel structure and three-dimensional visualization of the sample. The effect of water evaporation from livers during x-ray imaging on the visibility of blood vessels is delineated. The deformed vascular tree in a cancerous murine liver is imaged.