8 Other conceptual questions: (5 points each, 15 points total) a. Consider the setup of RHEED from a film of simple cubic lattice with atomically flat surface, draw Ewald sphere construction and use it to explain the expected diffraction pattern. b. Consider the evaporation from a Knudsen cell (see figure) it is well known that the area of the exit orifice A, at which the vapor pressure inside the Knudsen cell begins to decrease significantly from the saturated vapor pressure increases with decreasing the condensation coefficient. Please explain why. c. For growths under Frank-van der Merwe mode, explain the two distinctively different growth mode for the layer-by-layer formation of films and state the relative values of two length scales that cause the cross-over from one mode to the other (hint: think surface diffusion; feel free to draw figure to help illustrating your point) Ae