(b) Scattering from adjacent atoms in a row Interference from adjacent atoms in a row is constructive when the path lengths a cos 0 and a cos 0, are equal, so that the angle of incidence 0, equals the angle of reflection (scattering) 0.. (c) Scattering from atoms in adjacent rows Interference from atoms in adjacent rows is constructive when the path difference 2d sin0 is an integer number of wavelengths, as in Eq. (36.16). (a) Scattering of waves from a rectangular array Incident plane waves a cos e. acos0, Scatterers (e.g., atoms) d sine d sine

(b) Scattering from adjacent atoms in a row Interference from adjacent atoms in a row is constructive when the path lengths a cos 0 and a cos 0, are equal, so that the angle of incidence 0, equals the angle of reflection (scattering) 0.. (c) Scattering from atoms in adjacent rows Interference from atoms in adjacent rows is constructive when the path difference 2d sin0 is an integer number of wavelengths, as in Eq. (36.16). (a) Scattering of waves from a rectangular array Incident plane waves a cos e. acos0, Scatterers (e.g., atoms) d sine d sine