David Smith

Publications (3)6.67 Total impact

• Article: Experimental and theoretical investigation of electron attachment to SF(5)Cl.

  Jane M Van Doren, Thomas M Miller, Albert A Viggiano, Patrik Spanel, David Smith, Joseph C Bopp, Jürgen Troe
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  ABSTRACT: Thermal electron attachment to SF(5)Cl has been studied with the flowing afterglow Langmuir probe technique. The rate coefficient is moderate, 4.8(+/-1.2)x10(-8) cm(3) s(-1), and invariant with temperature over the temperature range of 300-550 K. The reaction is dissociative, forming mainly SF(5) (-)+Cl. Minor yields of Cl(-) and FCl(-) were also found. The yields of the minor channels increase slightly with temperature. Statistical unimolecular rate modeling is employed to elucidate the character of the dissociation pathways and to support the assumption that the dissociations involve the formation of metastable anionic SF(5)Cl(-).
  The Journal of Chemical Physics 04/2008; 128(9):094309. · 3.33 Impact Factor
• Article: Experimental and theoretical investigation of electron attachment to SF5Cl

  Jane M. Van Doren, Thomas M. Miller, Albert A. Viggiano, Patrik Španěl, David Smith, Joseph C. Bopp, Jürgen Troe
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  ABSTRACT: Thermal electron attachment to SF5Cl has been studied with the flowing afterglow Langmuir probe technique. The rate coefficient is moderate, 4.8(±1.2)×10−8 cm3 s−1, and invariant with temperature over the temperature range of 300–550 K. The reaction is dissociative, forming mainly SF5−+Cl. Minor yields of Cl− and FCl− were also found. The yields of the minor channels increase slightly with temperature. Statistical unimolecular rate modeling is employed to elucidate the character of the dissociation pathways and to support the assumption that the dissociations involve the formation of metastable anionic SF5Cl−.
  The Journal of Chemical Physics 03/2008; 128(9):094309-094309-8. · 3.33 Impact Factor
• Article: Mutual neutralization of simple and clustered positive and negative ions

  David Smith, Michael J. Church, Thomas M. Miller
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  ABSTRACT: Measurements are reported of the rate coefficients, α, for several ion–ion mutual neutralization reactions principally involving NH4+ ions and their ammonia clusters NH4+⋅ (NH3)1,2,3 with several different negative ions. The data were obtained utilizing an ion–ion flowing afterglow plasma combined with Langmuir probe diagnostics. Most of the measurements were obtained at 300 K although the NH4++Cl− reaction has also been studied at 220 and 430 K. Both the absolute magnitude of α and its temperature variation are shown to be in acceptable agreement with theoretical predictions. The α for the cluster ion reactions are very similar to those for the simpler ions, even when both positive and negative ions are large clusters, although an increase in the mean reaction cross section for the cluster ion reactions is discernible. All the α measured to date for both simple and cluster ion reactions, albeit for species of high electron affinity and over the limited temperature range of 180 to 530 K, are within the range (4–10) ×10−8 cm3 s−1, more marked variations occurring with temperature than with ionic mass.
  The Journal of Chemical Physics. 01/1978; 68(3):1224-1229.