Cluster molecular axis orientation dependence of secondary electron emission energy from carbon foils due to cluster impact

We report the effect of molecular axis orientation on the emission energy of secondary electrons. The projectile beam was 3.6 MeV Si₂⁺, and the target was C-foil with a thickness of 1.0 μg/cm². We performed a coincidence measurement of the image of fragments resulting from the Coulomb explosion of Si₂⁺ and the energy of secondary electrons emitted backward to the beam direction. The secondary electron yields at energies below 18 eV are discussed for Si₂⁺ projectile with parallel and perpendicular orientations to the beam direction, calculated theoretically using the electronic stopping power. (author)