Atomic-site-selected chemistry in the condensed phase induced by monochromatic soft x-rays

Core-hole relaxation processes following K-shell excitation of small molecules can produce excited molecular species, which can be trapped in the condensed phase and monitored in situ by Fourier transform Infrared spectroscopy. By identifying the core-hole decay products from its the vibrational structure and studying the photoproduct distribution as a function of excitation energy, excitation site information can be obtained on the dynamics and chemistry of decay processes producing these species. Tunable monochromatic soft x-rays from a synchrotron light source were utilized to create core-hole on a specific atomic site on the molecules.;In the concentration dependence studies of acetone in deuterium matrices the quantum yield was essentially constant (within the limit of experimental error) below the concentration 1:1000 and, increased very steeply at very high concentrations. It was clear that as one approaches to concentration regimes of 1 part in 1000 or less of acetone the unimolecular photochemical decomposition mechanisms prevail.;Molecular structural effects on the photodecomposition dynamics following core excitation processes revealed that in the aliphatic systems (5-Oxohexanenitrile, acetone, etc. isolated in D;These experiments illustrate the importance of target to host concentration, type of matrix host, molecular structure of the target molecules and the atomic-site of excitation in the soft x-ray photochemistry in the condensed phase.;The fragmentation of nitrous oxide in D...