eprintid: 16155 rev_number: 27 userid: 1291 dir: disk0/00/01/61/55 datestamp: 2012-11-07 19:21:53 lastmod: 2021-06-12 22:55:26 status_changed: 2012-11-07 19:21:53 type: article metadata_visibility: show item_issues_count: 0 eprint_status: archive creators_name: Relph, RA creators_name: Elliott, BM creators_name: Weddle, GH creators_name: Johnson, MA creators_name: Jing, D creators_name: Jordan, KD creators_email: creators_email: creators_email: creators_email: creators_email: creators_email: jordan@pitt.edu creators_id: creators_id: creators_id: creators_id: creators_id: creators_id: JORDAN title: Vibrationally induced interconversion of H-bonded NO 2- · H 2O isomers within NO 2- · H 2O·Ar m clusters using IR - IR pump - Probe through the OH and NO stretching vibrations ispublished: pub divisions: sch_as_chemistry full_text_status: public abstract: We introduce a method based on sequential application of vibrational predissociation spectroscopy to explore the high-amplitude rearrangements available in a small H-bonded complex that is vibrationally excited within a larger Ar cluster. The weakly bound Ar atoms play the role of a solvent in mediating the energy content of the embedded system, ultimately quenching it into local minima through evaporation. We demonstrate the approach on the NO 2-·H 2O binary hydrate, which is known to occur in two nearly isoenergetic isomeric forms. The scheme involves three stages of mass separation to select a particular NO 2-·H 2O·Ar m parent ion cluster prior to vibrational excitation and then isolate the NO 2-·H 2O·Ar fragment ions for interrogation using resonant vibrational predissociation with a second infrared laser. The initial vibrational excitation selectively energizes one of the isomers through one of its characteristic resonances while the predissociation spectrum of the NO 2-·H 2O· Ar fragment encodes the distribution of isomers present after Ar evaporation. Isomerization from the front- to backside form is found to occur upon excitation of the NO stretch near 1200 cm -1; although the reverse reaction is not observed upon excitation of the NO stretch, it is observed upon excitation of the higher-energy OH stretching fundamental near 3000 cm -1. We discuss these observations in the context of the calculated isomerization energetics, which focus on the minimum energy structures for the isomers as well as the transition states for their interconversion. © 2009 American Chemical Society. date: 2009-02-12 date_type: published publication: Journal of Physical Chemistry A volume: 113 number: 6 pagerange: 975 - 981 refereed: TRUE issn: 1089-5639 id_number: 10.1021/jp808283r pmid: 19152322 citation: Relph, RA and Elliott, BM and Weddle, GH and Johnson, MA and Jing, D and Jordan, KD (2009) Vibrationally induced interconversion of H-bonded NO 2- · H 2O isomers within NO 2- · H 2O·Ar m clusters using IR - IR pump - Probe through the OH and NO stretching vibrations. Journal of Physical Chemistry A, 113 (6). 975 - 981. ISSN 1089-5639 document_url: http://d-scholarship-dev.library.pitt.edu/16155/1/licence.txt