Suppression of fragment contributions to mass-selected resonance enhanced multiphoton ionization spectra of van der Waals clusters
1989; American Institute of Physics; Volume: 90; Issue: 3 Linguagem: Inglês
10.1063/1.455998
ISSN1520-9032
AutoresEvan J. Bieske, Mark W. Rainbird, Alan Knight,
Tópico(s)Spectroscopy and Quantum Chemical Studies
ResumoA technique is described for suppressing the contribution due to fragmentation of higher mass clusters in mass-selected resonance enhanced multiphoton ionization spectroscopy of weakly bound van der Waals (vdW) clusters formed in a skimmed supersonic expansion. Suppression is achieved by ionizing upstream from the extraction region of a time-of-flight mass spectrometer and by using a delayed voltage pulse to extract the ions. Normally, spectra associated with a particular cluster ion, e.g., AB+n will contain contributions from fragments formed by the dissociation of higher mass clusters, e.g., AB+n+m. However, with upstream ionization and delay extraction, AB+n fragments formed by AB+n+m dissociation that have different kinetic energy and altered trajectories from the directly ionized AB+n clusters, are not extracted efficiently and are hence discriminated against in detection. The technique is demonstrated with the aniline–argon vdW complex.
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