Question

1. Calculate the goniometer setting, in terms of 2$\theta$ required to observe the K$\alpha$1 lines for Fe (1.76Å), Se (0.992Å), and Ag (0.497Å) when the diffracting crystal is (a) topaz (b) LiF and (c ) NaCl.

2. Calculate the goniometer setting, in terms of 2$\theta$ required to observe the L$\beta$ 1 lines for Br at 8.126Å when the diffracting crystal is (a) ethylenediamine d-tartrate (b) ammonium dihydrogen phosphate.

note: in both cases you to select the crystal planes

Answer 1

a) The Bragy equation is given as na = 2d sind For Topaz, d=1.356 Far : 1X1.76= 2x1356 sini Feo ka at 1.76 År I = 40.46 For for Fe sekco.992 A) .: 20 = 8o go - 1X0.992= 2x1-356x sind 128= 42-go for se. For Ag ka at 0.497A 120 = 21.107 Fourty. b) For LIF, d=2.014 A Four se ka at o-992A : 1x1.76=2x2:014 sind 120= 28.50 Far se : | 20= 51.80 foor Fe For Ag ka at 0.497 A 1 x 0.497 - 2xL-014 SCH 120= 14.2 for Ag- c) Forgrad, d=2.820Ă 1 x 1.76 = 2 x 2.820 20= 36.40] four Fe. For For se 4 at 0.299 Å 120= 20.30 / Forse 1x 0.992=2X 2.820x sind Ag ka at 0.497 Ä 1x0.497 = 2x2.820 sind T20 = 10.10 For Ag