A beam of helium atoms, originating from a supersonic nozzle maintained at a temperature 400 K,...
A beam of helium atoms, originating from a supersonic nozzle maintained at a temperature 400 K, strike a closely packed nickel surface at normal incidence. The kinetic energy of the helium atoms is equal to 3 KĖTnozzle where ke is the Boltzmann constant. The molar mass of helium is 4.003 x 10-3 kg mor? Given that the spacing between the rows of nickel atoms is 240 pm calculate the angle to the perpendicular at which the fourth order diffraction peaks will be observed. (10 marks)