X-ray diffraction

Discussion in 'Physics' started by boks, May 25, 2009.

  1. boks

    Thread Starter Active Member

    Oct 10, 2008
    The relative height of the peaks in an XRD diffractogram are different from those given in the standard powder diffraction database (JCPDS card) for a certain oxide. What is the most likely explanation for the discrepancy between the obtained diffractogram from a thin film and the powder diffraction standard?
  2. TWRackers

    Active Member

    Dec 29, 2008
    I'm not sure if this is a quiz or if you're actually seeking an answer, but since there are no points off if I get it wrong, I'll give it a shot....

    How about interference between the surfaces of the thin film, in much the same way soap bubbles show colors due to interference at different wavelengths, some constructive, some destructive, and most somewhere in between?

    It's been many years since I've done any X-ray diffraction work on powders, never on thin films, so I'm just giving it a shot on first principles.

    I'm curious now what the correct answer is.

    ANOTHER THOUGHT: I remember powders would produce rings on the films in our physics lab's camera, and crystals produced dots. Would a thin film be closer to a crystalline structure or an amorphous structure?
  3. hemant kumar singh

    New Member

    Dec 2, 2008
    X-ray diffraction method to thin film has not been persued with vigor due to :-

    The great penetrating power of X rays means that with typical incident angles, their path length through films is too short to produce diffracted beams of sufficient intensity.Under such condition the substrate, rather than the film, dominates the scattered X-ray signal.;thus diffraction peaks from films require long counting time.