  In plasmonics, and particularly in plasmonic photochemistry, the effect of
hot-electron generation is an exciting phenomenon driving new fundamental and
applied research. However, obtaining a microscopic description of the
hot-electron states represents a challenging problem, limiting our capability
to design efficient nanoantennas exploiting these excited carriers. This paper
addresses this limitation and studies the spatial distributions of the
photophysical dynamic parameters controlling the local surface photochemistry
on a plasmonic nanocrystal. We found that the generation of energetic electrons
and holes in small plasmonic nanocrystals with complex shapes is strongly
position-dependent and anisotropic, whereas the phototemperature across the
nanocrystal surface is nearly uniform. Our formalism includes three mechanisms
for the generation of excited carriers: the Drude process, the surface-assisted
generation of hot-electrons in the sp-band, and the excitation of interband
d-holes. Our computations show that the hot-carrier generation originating from
these mechanisms reflects the internal structure of hot spots in nanocrystals
with complex shapes. The injection of energetic carriers and increased surface
phototemperature are driving forces for photocatalytic and photo-growth
processes on the surface of plasmonic nanostructures. Therefore, developing a
consistent microscopic theory of such processes is necessary for designing
efficient nanoantennas for photocatalytic applications.
