Effects of solvation on dissociative electron attachment to methyl iodide clusters |
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Authors: | JM Weber II Fabrikant E Leber M-W Ruf H Hotop |
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Institution: | Fachbereich Physik, Universit?t Kaiserslautern, 67663 Kaiserslautern, Germany, DE
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Abstract: | Using laser photoelectron attachment to methyl iodide clusters in a differentially-pumped seeded supersonic helium beam and
mass spectrometric ion detection, we have measured the rate coefficients for formation of (q = 0-2) ions over the electron energy range 0-100 meV with an effective energy width of about 2.5 meV. Whereas a prominent
vibrational Feshbach resonance just below the onset for the C-I stretch vibration ( ) is observed for dissociative attachment to monomers (yielding I- ions), only weak and broad structure, shifted to lower energies, is detected for formation of ions and essentially no structure is left in the attachment spectrum for . These observations are interpreted by model R-matrix calculations which successfully describe the DA cross-section for the monomer and qualitatively recover the trend
observed for cluster ion formation. For the clusters, the effects of increased electron-target long-range interaction and
of solvation as well as coupling to soft vibrational modes lead to strong broadening and shifting of the vibrational Feshbach
resonance and, ultimately, to its disappearance.
Received 29 November 1999 and Received in final form 14 January 2000 |
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Keywords: | PACS 34 80 Ht Dissociation and dissociative attachment by electron impact - 36 40 Qv Stability and fragmentation of clusters - 36 40 Wa Charged clusters |
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