How long does it take to melt a gold nanorod? A femtosecond pump-probe absorption spectroscopic study

Using pump-probe femtosecond transient absorption spectroscopy, we determin ed the rate of the bleach of absorption around 700-800 nm due to the longit udinal surface plasmon band of gold nanorods. Using TEM of the spotted, com pletely irradiated solutions suggest that the dominant products of the phot othermal conformation of the rods are spheres of comparable volume. This le ad to the conclusion that the melting of the rods is at least 30-35 ps, ind ependent of the power used (5-20 mu J) or the nanorod aspect ratio (1.9-3.7 ). (C) 1999 Elsevier Science B.V. All rights reserved.