Thank you so much sir!! Really I saw many videos but this one cleared all the doubts. You not only cleared doubts but also presented it so well with a beautiful ending. ☺
Thank you very much professor. The way you have explained the concept is so good and crystal clear now. Also, I strongly believe that you are a good teacher as you not only explained the concept but also highlighted the discovery people.
Sir its really amazing its a very good lecture sir. especially the Bragg's assumption on diffracted beam as the reflected beam considering the lattice planes. And the Son and Father got noble prize in 1915 , for their studies[ i completed masters in material science till now i don't know this fact]. Thank you so much sir for updating me.
Sir if you could upload your video on neutron diffraction method and electron diffraction method... That will be immensely helpful... Your lecture are something which I can say getting upto infinity by adding 1+1.... I am proud we have such lecturer in India too
We see a lot of scientists who made made path breaking discoveries, were not too brilliant. Instead, they thought outside the box..!! Similar case can be observed but in theory of relativity.
Sir the beginning of the class u r mention lave diffraction method [as said in last lecture] but the last lecture is inter planar spacing d hkl and not mention any lave technique.
Respected sir, about 8-10 months ago, I have seen your lecture on XRD. Unfortunately, it is not showing on youtube at this time. Can you send me the link related to that lecture?
🙏🙏👍Wow... Very deep knowledge and explaination... Isiliye mai sirf apke jaise Talented teachers ka hi Video dekhna psnd krta hu nhi to book se pdhta hu. kisi aise vaise teacher ka video nhi dekhta hu... Lekin dukh ki baat ye hai ki apke jaise deep knowledge vale teachers ki youtube pr kmi hai aur JHOLACHP teachers ki bhrmar hai
Sir, according to extinction rules, all reflections are allowed in monoatomic simple cubic crystal. Will 100 reflection be present in CsCl crystal which has a simple cubic lattice with two atom motif ?
Well, it really depends on what the heat treatment is doing to the microstructure. If some phase disappears then the peaks of that phase will also disappear. If some new phase appears the corresponding peaks will appear. If residual strains are relieved then the peak width will decrease. If grain size increases then also the peak width will decrease.
Sir, if the direction of incident beam is fixed then for a given set of lattice planes there is only one direction in which the specular reflection can occur. Then sir what is the significance of higher order reflections from a given set of planes. Sir if we keep indicent ray direction fixed shouldn't we get only we reflection direction for each set of planes? Also sir the laue's condition says that for every direction which satisfies the condition K' - K = G, we get a diffracted / reflected beam. That means for fixed incident direction we should get a large number of diffracted beams. I'm confused sir. I hope i'm able to convey my doubt clearly.
For a given plane in a SINGLE CRYSTAL (fixed d), and a given incident beam direction (fixed theta say theta_1) you may or may not get a diffraction depending upon whether Bragg's law is satisfied. And if the Bragg's law is satisfied for n=1, it is the first order diffraction. For the same incident beam in the same direction, you cannot get a second order (n=2) diffraction as it comes at a higher angle theta_2=cos^-1(2*lambda/2d) instead of theta_1=cos^-1(lambda/2d). For a POLYCRYSTALLINE sample (powder) the situation is different. There are many crystals with different orientations. So, some crystal may satisfy the condition for 1st order and some for second or higher order. In effect, you are changing theta by changing the orientation of the crystal even for a fixed incident beam. You may like to check following videos Ewald's sphere: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-hUWkaxTY3sI.htmlsi=u0dsTHe0B1pn-xxb X-ray Diffraction: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Z5aCuGxUPpI.htmlsi=5YCB342PEeZq4hMu
Thanks a lot for asking this question. In fact, there is no proof for the first part. It was an imaginative jump by WL. Bragg (son). The fact that we can explain the diffraction phenomena by this assumption (postulate) can be taken as proof. But there is no simple mathematical derivation like that for the second part.