A beam of 188-eV electrons is directed at normal incidence onto a crystal surface as shown in Fig. 39.4b. The m = 2 intensity maximum occurs at an angle θ = 60.6°.
(a) What is the spacing between adjacent atoms on the surface?
(b) At what other angle or angles is there an intensity maximum?
(c) For what electron energy (in electron volts) would the m = 1 intensity maximum occur at θ = 60.6°? For this energy, is there an m = 2 intensity maximum? Explain.