Angular momentum transfer from swift electrons to non-spherical nanoparticles within the dipolar approximation.

In this work, we study the angular momentum transfer from a single swift electron to non-spherical metallic nanoparticles, specifically investigating spheroidal and polyhedral (Platonic Solids) shapes. While previous research has predominantly focused on spherical nanoparticles, our work expands the knowledge by exploring various geometries. Employing classical electrodynamics and the small particle limit, we calculate the angular momentum transfer by integrating the spectral density, ensuring causality through Fourier-transform analysis.

Angular dynamics of small nanoparticles induced by non-vortex electron beams.

In this work, we present a theoretical study of the angular dynamics of small nanoparticles induced by fast non-vortex electron beams. General expressions for the torque and the angular momentum transferred from an electron to an arbitrary-but small-nanoparticle are obtained using a full-retarded classical electrodynamics approach, within the small particle limit. We applied this methodology to study a particular case of interest: the angular dynamics of spherical nanoparticles with homogeneous and isotropic electromagnetic responses.

Analysis of electromagnetic forces and causality in electron microscopy.

The non-physical effects on the transverse momentum transfer from fast electrons to gold nanoparticles associated to the use of non-causal dielectric functions are studied. A direct test of the causality based on the surface Kramers-Kronig relations is presented. This test is applied to the different dielectric function used to describe gold nanostructures in electron microscopy.

Analytical modeling of optical reflectivity of random plasmonic nano-monolayers.

In this paper, we compare three different models that have been used to interpret reflectivity measurements of supported monolayers of nanoparticles. Two of them: (i) isotropic Maxwell Garnett and (ii) anisotropic two-dimensional-dipolar model are based on an effective-medium approach, while the third one (iii) coherent-scattering model, lies within the framework of multiple-scattering theory. First, we briefly review, on physical grounds, the foundations of each model and write down the corresponding formulas for the calculation of the reflectivity.