Question
ANSWER THE QUESTION BELOW IN GIVEN PARTS
Show that the formula for low-energy electron diffraction (LEED), when the incident electrons are perpendicular to a crystal surface may be written as sin phi = [n h c] / [D (2 mec2 KE)1/2] where n is the order of the maximum, D is the atomic spacing, me is the mass of the electron, KE is the kinetic energy of the electron, and phi is the angle between the incident and diffracted beams, (b) Using this result, calculate the atomic spacing in a crystal that has consecutive diffraction maxima at phi =24. 1 degree and phi =54. 9 degree for 100-eV electrons.
Explanation / Answer
These are low-energy electrons, so they