4.5 Silver Clusters Reacting with Halogen
67
where Eq. (4.13) is responsible for the formation of [AgCl 2 ]
– , while Eqs. (4.14) and
(4.15) indicate likely pathways in forming [Ag n Cl 2 ]
– and [Ag n Cl]
– ; also an additional
arrow in each equation indicates possible successive reactions. Note that the [Ag n Cl]
–
and [Ag n Cl 2 ]
– species appearing in the larger mass range (8 ≤ n ≤ 14) display an odd–
even alternation. This agrees with previous theoretical findings that the calculated
incremental binding energies, spin excitation energies, and HOMO–LUMO gaps
of [Ag n ]
– clusters all display an even/odd oscillation, which corresponds to their
even/odd selective reactivity [94]. As found, the intensity ratio of [Ag 8 Cl]
– to [Ag 8 ]
–
is larger than that of the other observed [Ag n Cl]
– clusters and their correlated [Ag n ]
–
product clusters when 8 ≤ n ≤ 14. In view of the atomic electron configurations,
Ag:[Kr]4d
10 5s
1 , the Ag 8
– cluster exhibits 9 valence electrons and the delocalized
nearly free electron gas (NFEG) orbitals are described as |1S
2 | 1P
2 | 1P
4 | 2S
1 |.
Therefore, it is expected that Ag 8
– will behave similar to an alkali-metal atom and
hence their reactivity towards chlorine is expected to follow the “harpoon model”
[95, 96] with products of “Ag 8 Cl
–
+ Cl”. The well-known example of harpoon
mechanism was proposed to explain the reaction of K atoms with Br 2 where the K
atom plucks a Br atom out of the Br 2 molecule. An electron leaps from the metal atom
(i.e., a harpoon) to the halogen, resulting in a coulomb attraction between the metal
and halogen, and hence the cross section is extended for their reactive encounter
[96–101]. This will be discussed in Chap. 11 [102].
References
1. M. Walter, J. Akola, O. Lopez-Acevedo, P.D. Jadzinsky, G. Calero, C.J. Ackerson, R.L.
Whetten, H. Grönbeck, H. Häkkinen, Proc. Natl. Acad. Sci. USA 105, 9157–9162 (2008)
2. Z. Luo, A.W. Castleman, Acc. Chem. Res. 47, 2931–2940 (2014)
3. Z. Luo, A.C. Reber, M. Jia, W.H. Blades, S.N. Khanna, A.W. Castleman, Chem. Sci. 7,
3067–3074 (2016)
4. D.E. Bergeron, A.W. Castleman Jr., T. Morisato, S.N. Khanna, Science 304, 84–87 (2004)
5. D.E. Bergeron, P.J. Roach, A.W. Castleman Jr., N. Jones, S.N. Khanna, Science 307, 231–235
(2005)
6. S. Kamiguchi, S. Nagashima, K.I. Komori, M. Kodomari, T. Chihara, J. Cluster Sci. 18,
414–430 (2007)
7. Y.J. Ko, H. Wang, K. Pradhan, P. Koirala, A.K. Kandalam, K.H. Bowen, P. Jena, J. Chem.
Phys. 135, 244312 (2011)
8. F. Poineau, C.D. Malliakas, P.F. Weck, B.L. Scott, E.V. Johnstone, P.M. Forster, E. Kim, M.G.
Kanatzidis, K.R. Czerwinski, A.P. Sattelberger, J. Am. Chem. Soc. 133, 8814–8817 (2011)
9. C. Paduani, P. Jena, J. Nanopart. Res. 14, 1035 (2012)
10. B. Xu, R. Wang, X. Wang, Nanoscale 4, 2713–2719 (2012)
11. J.A.B. Abdalla, I.M. Riddlestone, R. Tirfoin, N. Phillips, J.I. Bates, S. Aldridge, Chem.
Commun. 49, 5547–5549 (2013)
12. A. Desireddy, B.E. Conn, J. Guo, B. Yoon, R.N. Barnett, B.M. Monahan, K. Kirschbaum,
W.P. Griffith, R.L. Whetten, U. Landman, T.P. Bigioni, Nature 501, 399–402 (2013)
13. Y.W. Li, S.H. Zhang, Q. Wang, P. Jena, J. Chem. Phys. 138, 054309 (2013)
14. W.D. Knight, K. Clemenger, W.A. Deheer, W.A. Saunders, M.Y. Chou, M.L. Cohen, Phys.
Rev. Lett. 52, 2141–2143 (1984)
15. R.E. Leuchtner, A.C. Harms, A.W. Castleman Jr., J. Chem. Phys. 91, 2753–2754 (1989)
67
where Eq. (4.13) is responsible for the formation of [AgCl 2 ]
– , while Eqs. (4.14) and
(4.15) indicate likely pathways in forming [Ag n Cl 2 ]
– and [Ag n Cl]
– ; also an additional
arrow in each equation indicates possible successive reactions. Note that the [Ag n Cl]
–
and [Ag n Cl 2 ]
– species appearing in the larger mass range (8 ≤ n ≤ 14) display an odd–
even alternation. This agrees with previous theoretical findings that the calculated
incremental binding energies, spin excitation energies, and HOMO–LUMO gaps
of [Ag n ]
– clusters all display an even/odd oscillation, which corresponds to their
even/odd selective reactivity [94]. As found, the intensity ratio of [Ag 8 Cl]
– to [Ag 8 ]
–
is larger than that of the other observed [Ag n Cl]
– clusters and their correlated [Ag n ]
–
product clusters when 8 ≤ n ≤ 14. In view of the atomic electron configurations,
Ag:[Kr]4d
10 5s
1 , the Ag 8
– cluster exhibits 9 valence electrons and the delocalized
nearly free electron gas (NFEG) orbitals are described as |1S
2 | 1P
2 | 1P
4 | 2S
1 |.
Therefore, it is expected that Ag 8
– will behave similar to an alkali-metal atom and
hence their reactivity towards chlorine is expected to follow the “harpoon model”
[95, 96] with products of “Ag 8 Cl
–
+ Cl”. The well-known example of harpoon
mechanism was proposed to explain the reaction of K atoms with Br 2 where the K
atom plucks a Br atom out of the Br 2 molecule. An electron leaps from the metal atom
(i.e., a harpoon) to the halogen, resulting in a coulomb attraction between the metal
and halogen, and hence the cross section is extended for their reactive encounter
[96–101]. This will be discussed in Chap. 11 [102].
References
1. M. Walter, J. Akola, O. Lopez-Acevedo, P.D. Jadzinsky, G. Calero, C.J. Ackerson, R.L.
Whetten, H. Grönbeck, H. Häkkinen, Proc. Natl. Acad. Sci. USA 105, 9157–9162 (2008)
2. Z. Luo, A.W. Castleman, Acc. Chem. Res. 47, 2931–2940 (2014)
3. Z. Luo, A.C. Reber, M. Jia, W.H. Blades, S.N. Khanna, A.W. Castleman, Chem. Sci. 7,
3067–3074 (2016)
4. D.E. Bergeron, A.W. Castleman Jr., T. Morisato, S.N. Khanna, Science 304, 84–87 (2004)
5. D.E. Bergeron, P.J. Roach, A.W. Castleman Jr., N. Jones, S.N. Khanna, Science 307, 231–235
(2005)
6. S. Kamiguchi, S. Nagashima, K.I. Komori, M. Kodomari, T. Chihara, J. Cluster Sci. 18,
414–430 (2007)
7. Y.J. Ko, H. Wang, K. Pradhan, P. Koirala, A.K. Kandalam, K.H. Bowen, P. Jena, J. Chem.
Phys. 135, 244312 (2011)
8. F. Poineau, C.D. Malliakas, P.F. Weck, B.L. Scott, E.V. Johnstone, P.M. Forster, E. Kim, M.G.
Kanatzidis, K.R. Czerwinski, A.P. Sattelberger, J. Am. Chem. Soc. 133, 8814–8817 (2011)
9. C. Paduani, P. Jena, J. Nanopart. Res. 14, 1035 (2012)
10. B. Xu, R. Wang, X. Wang, Nanoscale 4, 2713–2719 (2012)
11. J.A.B. Abdalla, I.M. Riddlestone, R. Tirfoin, N. Phillips, J.I. Bates, S. Aldridge, Chem.
Commun. 49, 5547–5549 (2013)
12. A. Desireddy, B.E. Conn, J. Guo, B. Yoon, R.N. Barnett, B.M. Monahan, K. Kirschbaum,
W.P. Griffith, R.L. Whetten, U. Landman, T.P. Bigioni, Nature 501, 399–402 (2013)
13. Y.W. Li, S.H. Zhang, Q. Wang, P. Jena, J. Chem. Phys. 138, 054309 (2013)
14. W.D. Knight, K. Clemenger, W.A. Deheer, W.A. Saunders, M.Y. Chou, M.L. Cohen, Phys.
Rev. Lett. 52, 2141–2143 (1984)
15. R.E. Leuchtner, A.C. Harms, A.W. Castleman Jr., J. Chem. Phys. 91, 2753–2754 (1989)