GE Water Provides Portfolio of Nanotech Membrane-Based Solutions - Aquananotechnology: Global Prospects - page 813

(a) (b)

S

Au

Au

Emission

Excitation

450 600 750 900 400 600 800

Wavelength (nm) Wavelength (nm)

FIGURE 26.1
(a) UV/Vis optical absorption spectrum of Au 25 (SG) 18 cluster. (b) Photoluminescence spectra of Au 25 (SG) 18 , which
exhibits emission at 690 nm. (Adapted from Shibu, E.S. et al., J. Phys. Chem C ., 112, 12168, 2008. Copyright with
permission from American Chemical Society.) Inset: crystal structure of Au 25 (SCH 2 CH 2 Ph) 18 . Total structure
is assumed as a shell of six (-RS-Au-SR-Au-SR-) units sitting on an Au 13 core. (Adapted from Zhu, M. et al.,
J. Am. Chem. Soc ., 130, 5883, 2008. Only Au and S atoms are shown. Copyright with permission from American
Chemical Society.)

1995 2025

Water withdrawal as percentage of
total available

Over 40%
40%-20%

20%-10%
Less than 10%

FIGURE 27.1
Water withdrawal rate as a percentage of total available water, projected till 2025. (From Service, R.F., Science ,
313, 1088, 2006.)