12.3 The Harpoon Mechanism
201
Figure 12.4a presents a mass spectrum of copper cluster anions after exposure
to chlorine gas, where the dominant products are assigned to [Cu n Cl n+1 ]
– (n = 1–
6) species which have been demonstrated as a starting point in the formation of
ionic crystals [117]. Besides these [Cu n Cl n+1 ]
– products, it is important to note that
[Cu 8 Cl]
– appears as a distinctive peak among the reaction products, in fact the only
peak that belongs to the [Cu n Cl]
– series. Figure 12.4b shows the reactivity of silver
cluster anions with chlorine, where three classes of reaction products are observed: (i)
[Ag n Cl n+1 ]
– , (ii) [Ag n Cl 2 ]
– and (iii) [Ag n Cl]
– . The [Ag n Cl n+1 ]
– species were observed
to only in the small mass range (n ≤ 4), seen as [AgCl 2 ]
– , [Ag 2 Cl 3 ]
– , [Ag 3 Cl 4 ]
– ,
and [Ag 4 Cl 5 ]
– , which were inferred to react based on the same mechanism as in
the formation of the [Cu n Cl n+1 ]
– series. When a [Ag n ]
– cluster collides with a Cl 2
molecule, the first-step reaction is expected to follow one of the following channels:
Fig. 12.4 The reaction of [Cu n ] – and [Ag n ] – clusters with Cl 2 . a A representative mass spectrum
showing the reaction product distribution of [Cu n ] – with Cl 2 (5.2-sccm flow rate); b mass distribution
of [Ag n ] – after reacting with Cl 2 (1.2-sccm flow rate). The peaks of [Cu 8 Cl] – and [Ag 8 Cl] – are
enlarged on the right of a and b, respectively
201
Figure 12.4a presents a mass spectrum of copper cluster anions after exposure
to chlorine gas, where the dominant products are assigned to [Cu n Cl n+1 ]
– (n = 1–
6) species which have been demonstrated as a starting point in the formation of
ionic crystals [117]. Besides these [Cu n Cl n+1 ]
– products, it is important to note that
[Cu 8 Cl]
– appears as a distinctive peak among the reaction products, in fact the only
peak that belongs to the [Cu n Cl]
– series. Figure 12.4b shows the reactivity of silver
cluster anions with chlorine, where three classes of reaction products are observed: (i)
[Ag n Cl n+1 ]
– , (ii) [Ag n Cl 2 ]
– and (iii) [Ag n Cl]
– . The [Ag n Cl n+1 ]
– species were observed
to only in the small mass range (n ≤ 4), seen as [AgCl 2 ]
– , [Ag 2 Cl 3 ]
– , [Ag 3 Cl 4 ]
– ,
and [Ag 4 Cl 5 ]
– , which were inferred to react based on the same mechanism as in
the formation of the [Cu n Cl n+1 ]
– series. When a [Ag n ]
– cluster collides with a Cl 2
molecule, the first-step reaction is expected to follow one of the following channels:
Fig. 12.4 The reaction of [Cu n ] – and [Ag n ] – clusters with Cl 2 . a A representative mass spectrum
showing the reaction product distribution of [Cu n ] – with Cl 2 (5.2-sccm flow rate); b mass distribution
of [Ag n ] – after reacting with Cl 2 (1.2-sccm flow rate). The peaks of [Cu 8 Cl] – and [Ag 8 Cl] – are
enlarged on the right of a and b, respectively