Kicking Around a Nano-Sized Ball

For the figure above the lower panel shows the double-to-single photoionization ratio of C60 (black circles) and a smooth curve (blue) through the data. The abscissa is the inverse of the square root of the excess energy; the excess energy is the photon energy (axis on top of the figure) minus the double-ionization threshold (=19eV). The upper panel shows the log of the data-curve ratio of the lower panel. The "humps" are at certain energies, namely whenever the corresponding de Broglie wavelength lambda matches a geometrical distance of the bucky ball such as the diameter (D) of the ball, the diameter of a hexagon (H), and the distance between two neighboring atoms (C).