X-ray transient absorption

Chen LX, Zhang X, Lockaid JV et al (2010) Excited-state molecular stractures captured by X-ray transient absorption spectroscopy a decade and beyond. Acta Cryst A 66 240-251... 

X-ray Transient Absorption Spectroscopy for Solar Energy Research... 

The aquated iron(III) ion is an oxidant. Reaction with reducing ligands probably proceeds through complexing. Rapid scan spectrophotometry of the Fe(III)-cysteine system shows a transient blue Fe(lII)-cysteine complex and formation of Fe(II) and cystine. The reduction of Fe(lII) by hydroquinone, in concentrated solution has been probed by stopped-flow linked to x-ray absorption spectrometry. The changing charge on the iron is thereby assessed. In the reaction of Fe(III) with a number of reducing transition metal ions M in acid, the rate law... 

Tomov IV, Rentzepis PM (2004) Ultrafast time-resolved transient stmctures of solids and liquids by means of extended X-ray absorption fine stmcture. ChemPhysChem 5 27-35... 

The term 1 or h indicates low or high coverage of adsorbed ethene, as inferred from ethene exposures.h TPD, temperature-programmed desorption LITD, laser-induced thermal desorption 1 FT-MS, Fourier-transform mass spectrometry SIMS, secondary-ion mass spectrometry MS, mass spectrometry T-NEXAFS, transient near-edge X-ray absorption fine structure spectroscopy RAIRS, reflection-absorption infrared spectroscopy. d Data for perdeut-erio species.1 Estimated value. 

Protonated polymethylbenzenes281 and the chlorohexamethylbenzenium cation,282 intermediates in aromatic electrophilic substitutions known as Wheland intermediates, have been isolated as crystalline salts, allowing investigators to obtain their X-ray crystal structure. Nitrosoarenium a complexes of various arenes were directly observed by transient absorption spectroscopy.283 Kochi presented a method combining appropriate instrumental techniques (X-ray crystallography, NMR, time-resolved UV-vis spectroscopy) for the observation, identification, and structural characterization of reactive intermediates fa and n complexes) in electrophilic aromatic substitution.284... 

Figure 4b shows the measured transient difference absorption spectrum as a function of the x-ray probe energy E, recorded 50 ps after laser excitation (data points with error bars) for a sample containing 80 mmol/1 solution of [Ru"(bpy)3]2+ in H2O. This transient contains all the electronic changes from the reactant state absorption spectrum, R E), to the product state absorption spectrum, P(E,t), at the time t after photoexcitation. WithXO being the fraction of excited state species at time t, the transient absorption spectrum T(E,t) is given by... 

Fig. 4. a) a) Static /.m-edge x- ray absorption spectrum of ground state [Rul (bpy)3]2+ (trace R), and excited state absorption spectrum (trace P) generated from the transient data curve T in (b) via eq. 2. b) Transient x-ray absorption spectrum (T) of photoexcited aqueous [Ru"(bpy)3]2+ measured 50 ps after laser excitation. 

Fig. 5. Scans of the pump-probe time delay between the laser pump pulse and the x-ray probe of the transient X-ray absorption signal of [Run(bpy)3]2+ (the x-ray energy is set at the minimum of the signal in fig. 20.b) over several tens of nsec (a) and in the psec time domain (b). The latter represents the cross-correlation signal between the 200 fs laser pulse and the 70-80 ps long x-ray pulse (indicated by the Gaussian-shaped derivative of the fit curve to the data).

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