The discrete dipole approximation

The discrete dipole approximation permits the calculation of the scattering and absorption cross-section of particles or arbitrary geometery. The first step in DDA modelling is to break the target geometry into a cubic array of dipoles.

In the case of the nanorods shown above (typically 10nm in diameter and with aspect ratios up to 6 or 8), we are particularly interested in the relationship between the spectrum generated by the rod and the spectra of the inscribed and exscribed cylinders.

Results from simulations of the extinction cross-section for these rods and cylinders can now be compared with some sample experimental data [1].

We are also interested in the spectra generated by geometries including triangular and hexagonal prisms.

References

1. Gold nanorod extinction spectra. SW Prescott and P Mulvaney. Journal of Applied Physics, 99, 123504, 2006.
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