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Pat's Perovskites
United States
Registrace 1. 01. 2012
This channel contains lectures and other educational material that pertain to the chemistry and physics of solids, particularly functional materials. Topics covered include solid state chemistry, materials chemistry, crystallography, and X-ray diffraction methods.
Holiday Game Beerspan Rules Explained
This video differs from all of the other content on this channel. It is not an educational video on chemistry or diffraction, rather it is an explanation of the rules to the game we play at the annual research group holiday party.
zhlédnutí: 586
Video
Diffraction Lecture 26: A Practical Guide to Rietveld Refinements
zhlédnutí 10KPřed 2 lety
We continue our discussion of Rietveld refinements with more details and a practical guide to guide you through a successful Rietveld refinement.
Diffraction Lecture 25: Rietveld Refinements
zhlédnutí 16KPřed 2 lety
The Rietveld method is used to refine the structures of crystals from powder diffraction data. Unlike single crystal methods, where the crystal structure is determined from structure factors extracted from a diffraction experiment, in the Rietveld method the entire powder diffraction pattern is fit. In this lecture we examine the general principles of the Rietveld method.
Diffraction Lecture 24: Structure Factors Part 2
zhlédnutí 4KPřed 2 lety
In the second half of this lecture on structure factors we explore the reasons behind the systematic absences associated with screw axes and glide planes, and see how the structure factors for centrosymmetric and noncentrosymmetric space groups differ. The latter part of the lecture covers Friedel's Law and Laue Groups.
Diffraction Lecture 23 - Structure Factors Part 1
zhlédnutí 9KPřed 2 lety
The structure factor F(hkl) arises from interference effects between X-rays scattered off of different atoms in the unit cell. All of the information about where the atoms are located in the unit cell is contained in the structure factor. In this lecture we look at the origins of the structure factor and see how they are calculated. We finish with some illustrative examples.
Diffraction Lecture 22: X-ray Absorption Effects
zhlédnutí 2,3KPřed 2 lety
As X-rays pass through a sample they are absorbed and this affects the intensities of various diffraction peaks. In this lecture we learn how to calculate the linear absorption coefficient for any substance from it's composition, density and the wavelength of the X-rays. Then we consider how to use this information when designing experiments and analyzing diffraction data.
Diffraction Lecture 21: Peak Intensities
zhlédnutí 5KPřed 2 lety
This is the first of several lectures that examine the factors that determine the intensities of diffraction peaks. Here we focus is mainly on effects other than the structure factor, including the polarization and Lorentz factors, multiplicities, and absorption effects.
Diffraction Lecture 20: Reflection Conditions
zhlédnutí 3,9KPřed 2 lety
In this lecture we see that for most space groups certain classes of diffraction peaks are systematically absent. Those peaks that are allowed are are said to follow specific reflection conditions. For example in a body centered space group only the reflection indices (hkl) where h k l is an even number are seen. We can use this information to dramatically narrow down the choice of space group.
Diffraction Lecture 19: Autoindexing Powder Diffraction Patterns
zhlédnutí 4,9KPřed 2 lety
In this lecture we discuss the use of computer programs for indexing powder diffraction patterns. The focus is primarily on the indexing routines in the software package Topas, but other programs are discussed as well.
Diffraction Lecture 18: Indexing Tetragonal and Hexagonal Patterns
zhlédnutí 15KPřed 2 lety
This is a continuation of lecture 17, where the procedure for indexing an X-ray powder diffraction pattern of a cubic material was illustrated. In this lecture we extend the technique to tetragonal and hexagonal crystal systems.
Diffraction Lecture 17: Indexing Diffraction Patterns of Cubic Crystals
zhlédnutí 30KPřed 2 lety
In this lecture we look at the X-ray powder diffraction pattern of a cubic material and see how to calculate the 2-theta values of the diffraction peaks. We see that the positions of each and every diffraction peak is determined by the length of the unit cell edge and the X-ray wavelength. We finish by manually indexing the diffraction pattern of MgO.
Diffraction Lecture 16: Lattice Planes and Interplanar Spacing
zhlédnutí 8KPřed 2 lety
In this lecture we see how the Bragg concept of diffraction (reflecting from parallel lattice planes) and the Laue concept of diffraction (scattering from atoms, typically in transmission) relate to one another. We review how to assign Miller Indices to lattice planes and calculate the spacing between families of parallel planes.
Diffraction Lecture 15: Reciprocal Space
zhlédnutí 18KPřed 2 lety
In this lecture we examine the relationship between the real space lattice that defines a crystal structure and its reciprocal space lattice. We then see the connection between the reciprocal space lattice and points of constructive interference that give rise to the diffraction pattern of the crystal.
Diffraction Lecture 14: Scattering in Two and Three Dimensions
zhlédnutí 6KPřed 2 lety
In this lecture we explore the conditions that lead to diffraction from two- and three-dimensional crystals.
Diffraction Lecture 13: Bragg's Law and Laue's Equations
zhlédnutí 17KPřed 2 lety
In this lecture we examine the geometric conditions that lead to diffraction of X-rays by crystals. First, we derive Bragg's Law, which gives the angle at which the scattered X-rays constructively interfere if the X-rays are partially reflected from parallel planes in a crystal. Next, we consider scattering in the forward direction (transmission) of an incoming beam of X-rays by a one-dimension...
Diffraction Lecture 12: Elastic Scattering of X-rays
zhlédnutí 5KPřed 2 lety
Diffraction Lecture 12: Elastic Scattering of X-rays
Diffraction Lecture 11: Crystallographic Symmetry and Physical Properties
zhlédnutí 2,5KPřed 2 lety
Diffraction Lecture 11: Crystallographic Symmetry and Physical Properties
Diffraction Lecture 10: Space Group Symmetry and the Structures of Molecular Crystals
zhlédnutí 2,3KPřed 2 lety
Diffraction Lecture 10: Space Group Symmetry and the Structures of Molecular Crystals
Diffraction Lecture 9: Space Groups and the Structures of Metallic and Ionic Crystals
zhlédnutí 2KPřed 2 lety
Diffraction Lecture 9: Space Groups and the Structures of Metallic and Ionic Crystals
Diffraction Lecture 8: Space Group Symmetry Part 2
zhlédnutí 4,6KPřed 2 lety
Diffraction Lecture 8: Space Group Symmetry Part 2
Diffraction Lecture 7: Space Group Symmetry Part 1
zhlédnutí 6KPřed 2 lety
Diffraction Lecture 7: Space Group Symmetry Part 1
Diffraction Lecture 6: 2D Plane Group Symmetry
zhlédnutí 10KPřed 2 lety
Diffraction Lecture 6: 2D Plane Group Symmetry
Diffraction Lecture 4: Travel Symmetry Operations
zhlédnutí 3,6KPřed 2 lety
Diffraction Lecture 4: Travel Symmetry Operations
Diffraction Lecture 3: Point Symmetry Operations
zhlédnutí 4,1KPřed 2 lety
Diffraction Lecture 3: Point Symmetry Operations
Diffraction Lecture 2: Translational Symmetry in Three Dimensions
zhlédnutí 4,3KPřed 2 lety
Diffraction Lecture 2: Translational Symmetry in Three Dimensions
Diffraction Lecture 1: Translational Symmetry in Two Dimensions
zhlédnutí 8KPřed 2 lety
Diffraction Lecture 1: Translational Symmetry in Two Dimensions
Lecture 40 Conductivity of Transition Metal Compounds
zhlédnutí 1,5KPřed 3 lety
Lecture 40 Conductivity of Transition Metal Compounds
Lecture 38 Conductivity and the Free Electron Model
zhlédnutí 3,6KPřed 3 lety
Lecture 38 Conductivity and the Free Electron Model
Thank you, finally I see more where these come from 🙏 My teaching materials just kind of skipped the geometry lol
is there a wrong about position of the a* and b* in 11:07?
Thx ❤
Thank you for the video
Dear Professor Woodward Thank you for the inspiring lectures! The example of the F atom chain is very beneficial to my understanding. I wonder whether you have some recommendation references on one-dimensional band structures like this. Thanks!
Could i have the articles
Please where this book
Best lecture Thanks sir!
Thank you sir for these highly structured and instructive lectures. Everything is perfect, especially the voice, and the way you present the lectures is fantastic and allows us to understand the phenomena studied from other angles. I'd like to ask you a question about lecture 12 in this first series of lectures (the lecture that precedes this lecture 13). I don't know whether you've forgotten to include it or whether there's just been a mistake in numbering. Thank you.
Even though English ist not my first language, I understood him better than my lecture in german(first language) so wow it’s very well explained👏👏
My Master's degree Tuitor..📝🤭..I will graduate in this school one day🇰🇪
Very well explained, a hundred thanks!
Thank you very much sir!
24:09 why (h^2+k^2+l^2)=(1/d^2)/0.0567 ? Can you please explain how we made that conclusion, please?
Dear Professor, I have a simple question: Kroneker's delta is defined based on the cubic lattice?
Super valuable for my PhD now. Thanks so much
What are you studying?
Thank you! There is something I didn't really get a grasp on though. What exactly is K in the K/a and where do we find it's value?
very clear . thank you so much
thanks!
Excellent and clear explanation, thank you
Amazing content, made things clearer, thanks a lot
Good lecture
thank you sir
501th like
Thanks for ur explicit explanation! great help; a supplement about that calculation of corundum:physics.nist.gov/PhysRefData/XrayMassCoef/tab3.html; I believe the website had moved to this one, and you need another website to seach for the energy: physics.nist.gov/PhysRefData/XrayTrans/Html/search.html
Makes you really think about the power of a metallic spacecraft skin that could take advantage of Jahn Teller Effects in combinatorial with Hall effects.
Thanks a lot. One of the best lectures I have seen in CZcams❤
Thank you very much, Can you do one for graphite?
nice explanation! Could you please explain highest occupied valance band and lowest unoccupied conduction band?
Thank you for this wonderfully clear introduction! Greetings from Cape Town!
What is the value of 'V' ?
Can you please share the pdf if possible ?
Thank you so much, professor. You saved my life.
How did you estimate the bond valence for oxygen?
Thanks a lot for this video!!
Keen I am. Visually impaired I am. Closed Caption a boon. terms used cc strange: 1. brewon? Brillouin?; 2. Debris one zone? I have listened up to 3:49. so far
I'm not sure how to convey this in a way that would be clear to a visually impaired person, but the terminology is Brillouin zone (pronounced bree-wan zone).
Incident beam bounces off Effects of unpolarized beam Single crystal diffraction Diffraction peaks Alpha polonium powder pattern Ups and downs of polonium Electron scaterring Equivalent reflection of single crystal diffraction Angular range Atomic factor Lorentz factor Crystal rotation Bounce ??? Bounces ???? Shattered lives Scaterred
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Visiting professor Patrick woodward
Crystal Reflection body centered Reflection Particular class of reflection h k 0 reflection h equal n reflection planes glides Crystal axes glide planes planes perpendicular to crystal axes affects reflections
A- centering B- centering C- centering Shuttering and centering Shuttering Shuttering Scattering Shuttering
Systematic absences Reflection ... Systematic absences . Reflection Systematic absences Reflection Systematic absences
Mountain peaks Mountain peaks Mountain peaks Powder pattern Spectroscopy
Graph plot of fourier series to frequency
Radio connect sir
Silicon Nacl
Doubled the number of 20 diffraction peaks Peaks Peaks Peaks Symmetry
m > 20 valid m > 10 pay attention m < 10 questionable for de wolff figure of merit interpretation
Figure of merit Figure of merit Figure of merit de wolff F index
Crystal impurity Crystal impurity Crystal impurity Cubic crystal Hexagonal crystal Tetragonal crystal