Transient absorption studies of single silver nanocubes

Single silver nanocubes have been studied by transient absorption spectroscopy. The traces show clear modulations due to coherently excited vibrational modes. The average period measured in the experiments was 18.6 +/- 1.7 ps, which is in excellent agreement with the calculated period for the breathing mode of the cubes. The distribution of the periods was also in a good agreement with that expected from the size distribution of the sample. The average damping time was 57.6 +/- 7.4 ps, which is approximately 2 times longer than the damping time measured in ensemble studies. There is only a weak correlation between the damping times and the periods. This implies that damping is affected by the particle's local environment and that there is significant heterogeneity in the environment.