In summary, the present study points to the success of the superatom model for describing the electronic structure of Au25(SCH2CH2Ph)18-. The fastest components in the relaxation scheme presented of Figure 4.3 reflect significant wavefunction overlap for states nominally localized to the Au13 core, whereas the slower core to semi-ring internal conversion process is consistent with wavefunctions partially localized to these two regions
132
of the cluster. The superatom model supports this real-space view of wavefunction localization. The cluster exhibits a short-lived optical anisotropy which distinguishes its transient electronic structure from that of a system with spherical symmetry. However, the rapid sub-picosecond decay in the anisotropy supports the superatom model’s approximation of the core as a quasi-spherical system (i.e., jellium sphere). The observation of an 80 cm-1 radial breathing mode local to the Au13 core suggests similarties between the mechanical properties of monolayer protected Au clusters and Au colloids. Future investigations will compare dynamics for a wider variety of Au cluster with different sizes. Examination of the optical response over a broader wavelength range (e.g. ultraviolet and near infrared) will further enhance physical insight.
133
4.5. REFERENCES
(1) Schultz, S.; Smith, D. R.; Mock, J. J.; Schultz, D. A. Proc. Natl. Acad. Sci.
2000, 97, 996-1001.
(2) Yguerabide, J.; Yguerabide, E. E. Anal. Biochem. 1998, 262, 137-156. (3) Antonello, S.; Holm, A. H.; Instuli, E.; Maran, F. J. Am. Chem. Soc. 2007,
129, 9836-9837.
(4) Pasquato, L.; Pengo, P.; Scrimin, P. J. Mater. Chem. 2004, 14, 3481-3487. (5) Wohltjen, H.; Snow, A. W. Anal. Chem. 1998, 70, 2856-2859.
(6) Nam, J.-M.; Thaxton, C. S.; Mirkin, C. A. Science 2003, 301, 1884-1886. (7) Anker, J. N.; Hall, W. P.; Lyandres, O.; Shah, N. C.; Van Duyne, R. P. Nature
Materials 2008, 7, 442-453.
(8) Pileni, M. P. J. Phys. Chem. C 2007, 111, 9019-9038.
(9) Myroshnychenko, V.; Rodríguez-Fernández, J.; Pastoriza-Santos, I.; Funston, A. M.; Novo, C.; Mulvaney, P.; Liz-Marzán, L. M.; de Abajo, F. J. G. Chem. Soc. Rev. 2008, 37, 1792-1805.
(10) Kelly, K. L.; Coronado, E.; Zhao, L. L.; Schatz, G. C. J. Phys. Chem. B 2003,
107, 668-677.
(11) Ellert, C.; Schmidt, M.; Schmitt, C.; Reiners, T.; Haberland, H. Phys. Rev. Lett. 1995, 75, 1731-1734.
(12) Wang, C. R. C.; Pollack, S.; Dahlseid, T. A.; Koretsky, G. M.; Kappes, M. M.
J. Chem. Phys. 1992, 96, 7931-7937.
(13) Murray, R. Chem. Rev. 2008, 108, 2688-2720.
(14) Zhu, M.; Aikens, C. M.; Hollander, F. J.; Schatz, G. C.; Jin, R. J. Am. Chem. Soc. 2008, 130, 5883-5885.
(15) Laaksonen, T.; Ruiz, V.; Liljeroth, P.; Quinn, B. M. Chem. Soc. Rev. 2008,
37, 1836-1846.
(16) Whetten, R. L.; Price, R. C. Science 2007, 318, 407-408.
(17) Heaven, M. W.; Dass, A.; White, P. S.; Holt, K. M.; Murray, R. W. J. Am. Chem. Soc. 2008, 130, 3754-3755.
134
(18) Jadzinsky, P. D.; Calero, G.; Ackerson, C. J.; Bushnell, D. A.; Kornberg, R. D. Science 2007, 318, 430-433.
(19) Zhu, M.; Eckenhoff, W. T.; Pintauer, T.; Jin, R. J. Phys. Chem. C 2008, 112, 14221-14224.
(20) Lee, D.; Donkers, R. L.; Wang, G.; Harper, A. S.; Murray, R. W. J. Am. Chem. Soc. 2004, 126, 6193-6199.
(21) Wang, G.; Huang, T.; Murray, R. W.; Menard, L.; Nuzzo, R. G. J. Am. Chem. Soc. 2005, 127, 812-813.
(22) Akola, J.; Walter, M.; Whetten, R. L.; Häkkinen, H.; Grönbeck, H. J. Am. Chem. Soc. 2008, 130, 3756-3757.
(23) Aikens, C. M. J. Phys. Chem. C 2008, 112, 19797-19800.
(24) Walter, M.; Akola, J.; Lopez-Acevedo, O.; Jadzinsky, P. D.; Calero, G.; Ackerson, C. J.; Whetten, R. L.; Grönbeck, H.; Häkkinen, H. Proc. Natl. Acad. Sci. 2008, 105, 9157-9162.
(25) Knight, W. D.; Clemenger, K.; de Heer, W. A.; Saunders, W. A.; Chou, M. Y.; Cohen, M. L. Phys. Rev. Lett. 1984, 52, 2141-2143.
(26) Goodno, G. D.; Dadusc, G.; Miller, R. J. D. J. Opt. Soc. Am. B 1998, 15, 1791-1794.
(27) Maznev, A. A.; Nelson, K. A.; Rogers, J. A. Opt. Lett. 1998, 23, 1319-1321. (28) Lepetit, L.; Chériaux, G.; Joffre, M. J. Opt. Soc. Am. B 1995, 12, 2467-2474. (29) Gallagher, S. M.; Albrecht, A. W.; Hybl, J. D.; Landin, B. L.; Rajaram, B.;
Jonas, D. M. J. Opt. Soc. Am. B 1998, 15, 2338-2345.
(30) Moran, A. M.; Park, S.; Scherer, N. F. J. Phys. Chem. B 2006, 110, 19771- 19783.
(31) Mukamel, S. Principles of Nonlinear Optical Spectroscopy; Oxford University Press: New York, 1995.
(32) Jonas, D. M. Annu. Rev. Phys. Chem. 2003, 54, 425-463.
(33) Horng, M. L.; Gardecki, J. A.; Papazyan, A.; Maroncelli, M. J. Phys. Chem.
1995, 99, 17311-17337.
(34) Sun, C.-K.; Vallée, F.; Acioli, L. H. Phys. Rev. B 1994, 50, 15337-15348. (35) Hodak, J. H.; Martini, I.; Hartland, G. V. J. Phys. Chem. B 1998, 102, 6958-
135
(36) Ahmadi, T. S.; Logunov, S. L.; El-Sayed, M. A. J. Phys. Chem. 1996, 100, 8053-8056.
(37) Park, S.; Pelton, M.; Liu, M.; Guyot-Sionnest, P.; Scherer, N. F. J. Phys. Chem. C 2007, 111, 116-123.
(38) Moran, A. M.; Nome, R. A.; Scherer, N. F. J. Chem. Phys. 2006, 125, 031101:031101-031104.
(39) Fleming, G. R. Chemical Applications of Ultrafast Spectroscopy; University Press: New York, 1986.
(40) Link, S.; El-Sayed, M. A.; Schaaf, T. G.; Whetten, R. L. Chem. Phys. Lett.
2002, 356, 240-246.
(41) Parker, J. F.; Choi, J.-P.; Wang, W.; Murray, R. W. J. Phys. Chem. C 2008,
112, 13976-13981.
(42) Andrews, D. L.; Thirunamachandran, T. J. Chem. Phys. 1977, 67, 5026-5033. (43) Hodak, J. H.; Henglein, A.; Hartland, G. V. J. Chem. Phys. 1999, 111, 8613-
8621.
(44) Tamura, A.; Higeta, K.; Ichinokawa, T. J. Phys. C: Solid State Phys. 1982, 15, 4975-4991.
(45) Kelley, A. M. J. Phys. Chem. A 1999, 103, 6891-6903.
(46) McHale, J. Molecular Spectroscopy; Prentice Hall: Upper Saddle Creek River, NJ,1999.
CHAPTER 5. NONLINEAR OPTICAL SIGNATURES OF CORE AND LIGAND