Dong, F., authorRocca, Jorge J., authorHeinbuch, S., authorBernstein, E. R., authorAmerican Institute of Physics, publisher2007-01-032007-01-032006Dong, F., et al., Single Photon Ionization of van der Waals Clusters with A Soft X-Ray Laser: (SO2)n and (SO2)n(H2O)m, Journal of Chemical Physics 125, no. 15 (October 21, 2006): 154317-1-154317-9.http://hdl.handle.net/10217/67527van der Waals cluster (SO2)n is investigated by using single photon ionization of a 26.5 eV soft x-ray laser. During the ionization process, neutral clusters suffer a small fragmentation because almost all energy is taken away by the photoelectron and a small part of the photon energy is deposited into the (SO2)n cluster. The distribution of (SO2)n clusters decreases roughly exponentially with increasing cluster size. The photoionization dissociation fraction of I[(SO2)n−1SO+]/I[(SO2)n+] decreases with increasing cluster size due to the formation of cluster. The metastable dissociation rate constants of (SO2)n+ are measured in the range of (0.6-1.5) × 104 s−1 for cluster sizes 5⩽n⩽16. Mixed SO2-H2O clusters are studied at different experimental conditions. At the condition of high SO2 concentration (20% SO2 partial pressure), (SO2)n+ cluster ions dominate the mass spectrum, and the unprotonated mixed cluster ions (SO2)nH2O+ (1⩽n⩽5) are observed. At the condition of low SO2 concentration (5% SO2 partial pressure) (H2O)nH+ cluster ions are the dominant signals, and protonated cluster ions (SO2)(H2O)nH+ are observed. The mixed clusters, containing only one SO2 or H2O molecule, SO2(H2O)nH+ and (SO2)nH2O+ are observed, respectively.born digitalarticleseng©2006 American Institute of Physics.Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.Text