Inelastic Scattering of X-Rays by Light Metals

The scattering cross section of X-rays inelastically scattered by an electron gas is calculated in the random phase approximation, for various scattering angles, making use of the formula previously derived by Ohmura and Matsudaira. When the angle is small, the profile deviates from the inverse parabolla due to the pauli exclusion principle and to the electron-electron interaction. Especially when the angle is near θ c , corresponding to the plasma cut-off wave number, a pronounced peak appears, reflecting plasmon emission. It is also shown that if a scattering angle is a little larger than θ c , yet the “plasmon peak” survives. These features are in excellent agreement with the experiments of Suzuki and Tanokura, and Alexandropoulos.