  Previous research has shown that gold nanoparticles immersed in water in an
optical vortex lattice formed by the perpendicular intersection of two standing
light waves with a \pi/2 rad phase difference will experience enhanced
dispersion that scales with the intensity of the incident laser. We show that
flexible nanoscale dumbbells (created by attaching two such gold particles by
means of a polymer chain) in the same field display different types of motion
depending on the chain length and field intensity. We have not disregarded the
secondary optical forces due to light scattering. The dumbbells may disperse,
rotate or remain trapped. For some values of the parameters, the (enhanced)
dispersion possesses a displacement distribution with exponential tails, making
the motion anomalous, though Brownian.
