Spatiotemporal reaction kinetics of an ultrafast photoreaction pathway visualized by time-resolved liquid x-ray diffraction Export

@article{PNAS2006TKKim, abstract = {10.1073/pnas.0601958103 We have studied the reaction dynamics for HgI in methanol by using time-resolved x-ray diffraction (TRXD). Although numerous time-resolved spectroscopic studies have provided ample information about the early dynamics of HgI, a comprehensive reaction mechanism in the solution phase spanning from picoseconds up to microseconds has been lacking. Here we show that TRXD can provide this information directly and quantitatively. Picosecond optical pulses triggered the dissociation of HgI, and 100-ps-long x-ray pulses from a synchrotron probed the evolving structures over a wide temporal range. To theoretically explain the diffracted intensities, the structural signal from the solute, the local structure around the solute, and the hydrodynamics of bulk solvents were considered in the analysis. The results in this work demonstrate that the determination of transient states in solution is strongly correlated with solvent energetics, and TRXD can be used as an ultrafast calorimeter. It also is shown that a manifold of structural channels can be resolved at the same time if the measurements are accurate enough and that global analysis is applied. The rate coefficients for the reactions were obtained by fitting our model against the experimental data in one global fit including all -values and time delays. The comparison between all putative reaction channels confirms that two-body dissociation is the dominant dissociation pathway. After this primary bond breakage, two parallel channels proceed. Transient HgI associates nongeminately with an iodine atom to form HgI, and I is formed by nongeminate association of two iodine atoms.}, author = {Kim, Tae K. and Lorenc, Maciej and Lee, Jae H. and Lo Russo, Manuela and Kim, Joonghan and Cammarata, Marco and Kong, Qingyu and Noel, Sylvie and Plech, Anton and Wulff, Michael and Ihee, Hyotcherl}, citeulike-article-id = {3380800}, citeulike-linkout-0 = {http://dx.doi.org/10.1073/pnas.0601958103}, citeulike-linkout-1 = {http://www.pnas.org/content/103/25/9410.abstract}, citeulike-linkout-2 = {http://www.pnas.org/content/103/25/9410.full.pdf}, citeulike-linkout-3 = {http://view.ncbi.nlm.nih.gov/pubmed/16772380}, citeulike-linkout-4 = {http://www.hubmed.org/display.cgi?uids=16772380}, day = {20}, doi = {10.1073/pnas.0601958103}, journal = {Proceedings of the National Academy of Sciences}, keywords = {bond-breaking, hgi, hydrodynamics, liquid-phase, molecular-structural-dynamics, solvent, transient-structure, txrd}, month = {June}, number = {25}, pages = {9410--9415}, posted-at = {2008-10-06 23:33:10}, priority = {2}, title = {Spatiotemporal reaction kinetics of an ultrafast photoreaction pathway visualized by time-resolved liquid x-ray diffraction}, url = {http://dx.doi.org/10.1073/pnas.0601958103}, volume = {103}, year = {2006} }

TY - JOUR ID - PNAS2006TKKim L3 - citeulike-article-id:3380800 N2 - 10.1073/pnas.0601958103 We have studied the reaction dynamics for HgI in methanol by using time-resolved x-ray diffraction (TRXD). Although numerous time-resolved spectroscopic studies have provided ample information about the early dynamics of HgI, a comprehensive reaction mechanism in the solution phase spanning from picoseconds up to microseconds has been lacking. Here we show that TRXD can provide this information directly and quantitatively. Picosecond optical pulses triggered the dissociation of HgI, and 100-ps-long x-ray pulses from a synchrotron probed the evolving structures over a wide temporal range. To theoretically explain the diffracted intensities, the structural signal from the solute, the local structure around the solute, and the hydrodynamics of bulk solvents were considered in the analysis. The results in this work demonstrate that the determination of transient states in solution is strongly correlated with solvent energetics, and TRXD can be used as an ultrafast calorimeter. It also is shown that a manifold of structural channels can be resolved at the same time if the measurements are accurate enough and that global analysis is applied. The rate coefficients for the reactions were obtained by fitting our model against the experimental data in one global fit including all -values and time delays. The comparison between all putative reaction channels confirms that two-body dissociation is the dominant dissociation pathway. After this primary bond breakage, two parallel channels proceed. Transient HgI associates nongeminately with an iodine atom to form HgI, and I is formed by nongeminate association of two iodine atoms. IS - 25 JF - Proceedings of the National Academy of Sciences EP - 9415 TI - Spatiotemporal reaction kinetics of an ultrafast photoreaction pathway visualized by time-resolved liquid x-ray diffraction VL - 103 SP - 9410 KW - bond-breaking KW - hgi KW - hydrodynamics KW - liquid-phase KW - molecular-structural-dynamics KW - solvent KW - transient-structure KW - txrd AU - Kim, Tae AU - Lorenc, Maciej AU - Lee, Jae AU - Lo Russo, Manuela AU - Kim, Joonghan AU - Cammarata, Marco AU - Kong, Qingyu AU - Noel, Sylvie AU - Plech, Anton AU - Wulff, Michael AU - Ihee, Hyotcherl PY - 2006/06/20/ UR - http://dx.doi.org/10.1073/pnas.0601958103 ER -