<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mizuse, Kenta</style></author><author><style face="normal" font="default" size="100%">Jer-Lai Kuo</style></author><author><style face="normal" font="default" size="100%">Fujii, Asuka</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Structural trends of ionized water networks: Infrared spectroscopy of water cluster radical cations (H2O)n+ (n = 3-11)</style></title><secondary-title><style face="normal" font="default" size="100%">Chem. Sci.</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2011</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1039/C0SC00604A</style></url></web-urls></urls><publisher><style face="normal" font="default" size="100%">The Royal Society of Chemistry</style></publisher><volume><style face="normal" font="default" size="100%">2</style></volume><pages><style face="normal" font="default" size="100%">868-876</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;The nature of water networks exposed to ionizing radiation is important in various radiation-related chemistry and biology. To understand structural evolution of ionized water networks at the molecular level{,} we report here infrared spectra of water cluster radical cations (H2O)n+ (n = 3 - 11) in the gas phase. Spectral features of free OH stretch modes are quite similar to those of protonated water clusters H+(H2O)n{,} of which the hydrogen-bond network structures have been revealed. In addition{,} we observed an extra band attributed to the stretch of an OH radical in (H2O)n+. These results indicate that nominal (H2O)n+ should be regarded as H+(H2O)n-1(OH) motifs having similar network shapes to those of H+(H2O)n. We also analyzed hydrogen-bonded OH stretch bands and found that hydrogen-bond strength is a key factor to determine the position of the OH radical relative to the protonated site (H3O+/H5O2+). Because an OH radical is a weaker hydrogen bond acceptor than water{,} the first solvation shell of the protonated site is preferentially filled with water. As a result{,} the OH radical is separated from the protonated (charged) site by at least one water molecule in n [greater-than-or-equal] 5 clusters. This result shows the instability of the H3O+-OH ion-radical contact pair in water networks{,} and implies the higher mobility of the OH radical due to its release from the charged site. Observed structural preferences are confirmed both in cold and warm cluster ion sources.&lt;/p&gt;
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