The plane will scatter, and all atoms in the plane will scatter in phase if angle of incidence equals angle of reflection. this is how a mirror reflects. Furthermore all the parallel planes will also reflect at this angle. Trouble is the beams scattered from the different parallel planes are systematically out of phase with each other unless Bragg's law is met for that set of planes, so interference is destructive and adds up to nothing. At least that's how I understand it, eab
On 07/08/2014 03:53 PM, Kianoush Sadre-Bazzaz wrote:
Hi If a sample of powder crystal (say Nickel) is shot with monochromatic x-rays, one will observe reflections from planes that satisfy Bragg's Law. For Ni the first four planes are (111, 200, 202, 311) with 2theta (44, 52, 76, 93 degrees) respectively. Why doesn't one observe a reflection at, say, 45 degrees? There will be a grain oriented in the powder such that x-rays reflect at 45 degrees and so forth. I would expect a continuum of reflections... thanks for the insight. Kianoush
