64
4 Halogenation of Metal Clusters
Fig. 4.6 (Upper) Reaction pathways of Al 13
− , Al 13 I − and Al 13 I 2
− with methanol. The lowest
energy reaction pathways with methanol for the ground states of (a) Al 13
− , (b) Al 13 I − , and
(c) Al 13 I 2
− . (Below) Reaction pathways of Al 14
− , Al 14 I − and Al 14 I 3
− clusters with methanol.
The lowest energy reaction pathways with methanol for the ground states of (d) Al 14
− , (e) Al 14 I − ,
and (f) Al 14 I 3
− . Al atoms are shown in light blue, I atoms in purple. HOMOs are red and LUMOs
blue
4.4 Ionic Crystal Growth of Cu n Cl n+1
−
Within the middle school chemistry textbook, there is an interesting experiment
that, copper scraps burn in chlorine and result in copper chloride by noting the final
products in water to display blue solution. But in lab experiments, it is known that
chlorine is slightly more selective in reacting with most metals and heavier nonmetals.
In 1986, the surface chlorination behavior of copper has been investigated using Xray photoemission technique [56]. It was found that, a surface layer of CuCl x could be
formed at C1 2 exposure, with a likely varying value of x (0–2) as a function of the gas
pressure and the exposure time. Regarding this topic, a study towards the reactivity of
copper clusters with chlorine has unveiled the intrinsic nature [57]. Figure 4.7 shows
the mass spectrum of Cu n
− clusters, produced via the MagS-source, in the absence
and presence of chlorine. The inset images show the different isotope combinations
of copper, as well as a sketch showing the building blocks Cu n Cl n+1
− in growing ionic
crystals. It is notable that when chlorine was introduced into the fast-flow reactor, all
the original Cu n
− clusters disappeared due to the violent gas-phase reactivity between
chlorine and copper cluster anions except a weak intensity of Cu 7
− which is known to
be a stable species with a closed shell of eight electrons according to the jellium model
[15, 24, 58]. Among the observed Cu n Cl n+1
− species, CuCl 2
− dominates the products,
and the following Cu 2 Cl 3
− , Cu 3 Cl 4
− , Cu 4 Cl 5
− , Cu 5 Cl 6
− , and Cu 6 Cl 7
− in the mass
spectra exhibit an exponential decay with increasing values of n with independence
of the quantities of chlorine being introduced. With an examination on the integral
intensity for the Cu n Cl n+1
− species, a fitting curve based on exponential function was
4 Halogenation of Metal Clusters
Fig. 4.6 (Upper) Reaction pathways of Al 13
− , Al 13 I − and Al 13 I 2
− with methanol. The lowest
energy reaction pathways with methanol for the ground states of (a) Al 13
− , (b) Al 13 I − , and
(c) Al 13 I 2
− . (Below) Reaction pathways of Al 14
− , Al 14 I − and Al 14 I 3
− clusters with methanol.
The lowest energy reaction pathways with methanol for the ground states of (d) Al 14
− , (e) Al 14 I − ,
and (f) Al 14 I 3
− . Al atoms are shown in light blue, I atoms in purple. HOMOs are red and LUMOs
blue
4.4 Ionic Crystal Growth of Cu n Cl n+1
−
Within the middle school chemistry textbook, there is an interesting experiment
that, copper scraps burn in chlorine and result in copper chloride by noting the final
products in water to display blue solution. But in lab experiments, it is known that
chlorine is slightly more selective in reacting with most metals and heavier nonmetals.
In 1986, the surface chlorination behavior of copper has been investigated using Xray photoemission technique [56]. It was found that, a surface layer of CuCl x could be
formed at C1 2 exposure, with a likely varying value of x (0–2) as a function of the gas
pressure and the exposure time. Regarding this topic, a study towards the reactivity of
copper clusters with chlorine has unveiled the intrinsic nature [57]. Figure 4.7 shows
the mass spectrum of Cu n
− clusters, produced via the MagS-source, in the absence
and presence of chlorine. The inset images show the different isotope combinations
of copper, as well as a sketch showing the building blocks Cu n Cl n+1
− in growing ionic
crystals. It is notable that when chlorine was introduced into the fast-flow reactor, all
the original Cu n
− clusters disappeared due to the violent gas-phase reactivity between
chlorine and copper cluster anions except a weak intensity of Cu 7
− which is known to
be a stable species with a closed shell of eight electrons according to the jellium model
[15, 24, 58]. Among the observed Cu n Cl n+1
− species, CuCl 2
− dominates the products,
and the following Cu 2 Cl 3
− , Cu 3 Cl 4
− , Cu 4 Cl 5
− , Cu 5 Cl 6
− , and Cu 6 Cl 7
− in the mass
spectra exhibit an exponential decay with increasing values of n with independence
of the quantities of chlorine being introduced. With an examination on the integral
intensity for the Cu n Cl n+1
− species, a fitting curve based on exponential function was