Electron energy loss spectra of NTCDA organic films

The electron energy loss (EEL) spectra of thin NTCDA films on the ZnO(0001) surface were measured. In the low-energy range (< 60 eV), the EEL spectra (displaying the characteristic loss peaks at E-loss = 4.0, 5.6, 12.5, and 1 4.5 eV) reflect the structure of transitions between the valence and conduc tion bands. As the primary electron energy increases, the dominating energy losses are due to the excitation of plasma oscillations at (h) over bar om ega (1) = 6.5 eV (pi plasmon) and (h) over bar omega (2) = 25 eV (pi- sigma plasmon). (C) 2001 MAIK "Nauka/Interperiodica".