x-ray diffraction(2)

Slide 1: 

PRINCIPLE INSTRUMENTATION OF X-RAY DIFFRACTION TECHNIQUE AND BY B.SARIKA

CONTENTS: 

CONTENTS DEFINITION GENERATION OF X-RAYS TYPES OF SPECTRA X-RAY TECHNIQUES GENERAL THEORY PRINCIPLE INSTRUMENTATION APPLICATIONS CONCLUSIONS REFERENCES

X-RAYS: 

X-RAYS 1 .x-rays are short wave length electromagnetic radiations produced by the deceleration of high energy electrons or by electronic transitions of electrons in the inner orbital of atoms 2 .X-ray region - 0.1to100 A ˚ 3 .Analytical purpose- 0.7 to 2 A ˚

GENERATION OF X-RAYS: 

GENERATION OF X-RAYS By bombarding matter by High energy electrons X-ray photons By use of radioactive source From synchrotron radiation Cornell-high-energy synchrotron radiation laboratory Stanford synchrotron radiation laboratory Brookhaven national laboratory

TYPES OF SPECTRA: 

TYPES OF SPECTRA LINE SPECTRA : Produced by primary X-rays CONTINUOUS SPECTRA OR WHITE RADIATION OR BREMSSTRAHLUNG RADIATION: Produced by high energy electrons

X-RAY TECHNIQUES: 

X-RAY TECHNIQUES X-RAY ABSORPTION METHOD X-RAY DIFFRACTION METHOD X-RAY FLOURESCENCE METHOD

Slide 7: 

‘ K ' X-RAYS E =E - E E=Energy of L-shell electrons E =Energy of K-shell electrons µ= E -E h 1 k L K K L L K

GENERAL THEORY 1)origin of x-rays 2)Interaction of x-rays with matter ORIGIN OF X-RAYS -BOHR’S ATOMIC MODEL: 

GENERAL THEORY 1)origin of x-rays 2)Interaction of x-rays with matter ORIGIN OF X-RAYS -BOHR’S ATOMIC MODEL

ENERGY LEVEL TRANSITIONS: 

ENERGY LEVEL TRANSITIONS

TYPICAL SPECTRUM EMITTED BY COPPER TARGET: 

TYPICAL SPECTRUM EMITTED BY COPPER TARGET

λmin=hc/eV h=plank’s constant c=speed of light in vaccum e=charge on electron V=accelerating voltage applied to x-ray tube By substituting these values, : 

λ min=hc/eV h=plank’s constant c=speed of light in vaccum e=charge on electron V=accelerating voltage applied to x-ray tube By substituting these values,

: 

λmin =12,400 V λ OF MAXIMUM INTENSITY=1.5× λ min MOSELEY’S LAW C =a(Z- σ ) λ 2

PRINCIPLE OF X-RAY DIFFRACTION METHOD: 

PRINCIPLE OF X-RAY DIFFRACTION METHOD

Slide 15: 

“ Constructive interference of the reflected of the reflected beams emerging from two different planes will take place if the path lengths of two rays is equal to whole number of wavelengths”. for constructive interference, n λ =2dsin Ф this is called as BRAGG’S LAW

INSTRUMENTATION: 

INSTRUMENTATION Production of x-rays Collimator Monochromator a.Filter b.Crystal monochromator Detectors a.Photographic methods b.Counter methods Geiger muller tube counter Proportional counter Scintillation counter Solid state semi-conductor detector Semi-conductor detectors

INSTRUMENTATION: 

INSTRUMENTATION

PRODUCTION OF X-RAYS-COOLIDGE TUBE: 

PRODUCTION OF X-RAYS-COOLIDGE TUBE

COLLIMATOR SYSTEM : 

COLLIMATOR SYSTEM

CRYSTAL MONOCHROMATORS: 

CRYSTAL MONOCHROMATORS

TYPES OF MONOCHROMATORS: 

TYPES OF MONOCHROMATORS 1.Flat crystal monochromator 2.Curved crystal monochromator Materials used- Nacl,LiF,quartz etc,.

DETECTORS: 

DETECTORS Photographic methods D=logIo/I Counter methods Geiger-muller tube counter Proportional counter Scintillation detector Solid-state semi-conductor detector Semi conductor detectors:si(Li) &Ge(Li)

DETECTORS-GEIGER MULLER TUBE COUNTER: 

DETECTORS-GEIGER MULLER TUBE COUNTER

GEIGER-MULLER TUBE: 

GEIGER-MULLER TUBE Filled with inert gases like argon. Positive potential=800-2500volts ADVANTAGES: inexpensive,trouble free detector,higher signal. DISADVANTAGES: used only for counting low rates,efficiency falls off rapidly at λ <1A°,cannot be used to measure energy of ionising radiation.

SCINTILLATION DETECTOR: 

SCINTILLATION DETECTOR

SCHEMATIC DIAGRAM OF Si(Li) DETECTOR: 

SCHEMATIC DIAGRAM OF Si(Li) DETECTOR

CRYSTAL DIFFRACTION: 

CRYSTAL DIFFRACTION

X-RAY DIFFRACTION METHODS: 

X-RAY DIFFRACTION METHODS 1.Laue’s photographic method Transmission method Back reflection method 2.Bragg’s X-ray spectrometer method 3.Rotating crystal method 4.Powder method

LAUE’S PHOTOGRAPHIC METHOD: 

LAUE’S PHOTOGRAPHIC METHOD

BRAGG’S IONISATION SPECTROMETRE: 

BRAGG’S IONISATION SPECTROMETRE

DIFFRACTION PATTERN OF A SINGLE CRYSTAL OF AN INORGANIC SALT: 

DIFFRACTION PATTERN OF A SINGLE CRYSTAL OF AN INORGANIC SALT

ROTATING CRYSTAL METHOD: 

ROTATING CRYSTAL METHOD COMPLETE ROTATING METHOD OSCILLATION METHOD

POWDER CRYSTAL METHOD: 

POWDER CRYSTAL METHOD

SCHEMATIC DIAGRAM OF POWDER CRYSTAL METHOD: 

SCHEMATIC DIAGRAM OF POWDER CRYSTAL METHOD

APPLICATIONS: 

APPLICATIONS Structure of crystals Polymer characterisation State of anneal in metals Particle size determination Spot counting method Broadening of diffraction lines Low-angle scattering 5.Applications of diffraction methods to complexes Determination of cis-trans isomerism Determination of linkage isomerism 6.Miscellaneous applications

1.STRUCTURE OF CRYSTALS: 

1.STRUCTURE OF CRYSTALS a -x-ray pattern of salt Nacl b -x-ray pattern of salt Kcl c -x-ray pattern of mixture of Nacl &Kcl d -x-ray pattern of a powder mixed crystal of Nacl & Kcl

2.POLYMER CHARACTERISATION: 

2.POLYMER CHARACTERISATION Determine degree of crystanillity Non-crystalline portion scatters x-ray beam to give a continuous background(amorphous materials) Crystalline portion causes diffraction lines that are not continuous.(crystalline materials)

3.STATE OF ANNEAL IN METALS: 

3.STATE OF ANNEAL IN METALS 4.PARTICLE SIZE DETERMINATION Spot counting method : v=V. δθ .cos θ /2n V =volume of individual crystallite V=total volume irradiated n=no. of spots in diffraction ring δθ =divergence of x-ray beam

APPLICATIONS OF DIFFRACTION METHODS TO COMPLEXES: 

APPLICATIONS OF DIFFRACTION METHODS TO COMPLEXES a)Determination of cis-Trans Isomerism : Bis(pyridine-2-carboxamido)nickle(II) chloride b)Determination of linkage isomerism : Biuret+copper(II)=pottassium bis(biureto)cuprate(II)tetrahydrate

MISCELLANEOUS APPLICATIONS: 

MISCELLANEOUS APPLICATIONS Soil classification based on crystallinity Analysis of industrial dusts Assessment of weathering & degradation of minerals & polymers Study of corrosion products Examination of tooth enamel & dentine Examination of bone state & tissue state Structure of DNA&RNA

CRYSTAL TONOGRAPHY: 

CRYSTAL TONOGRAPHY

CONCLUSIONS: 

CONCLUSIONS For materials including metals, minerals, plastics, pharmaceuticals and semiconductors XRD apparatus provide highly accurate tools for non-destructive analysis. The diffraction systems are also supported by an extensive range of application software.

REFERENCES: 

REFERENCES 1)Instrumental methods of chemical analysis ,B.K.sharma,17 th edition 1997-1998,GOEL publishing house.page no:329-359 2)Principles of instrumental analysis,5 th edition ,by Dougles a.skoog,f.James holles,Timothy A.Niemen.page no:277-298 3)Instrumental methods of chemical analysis ,Gurudeep R.chatwal,sham k.anand,Himalaya publications page no:2.303-2.332

Slide 44: 

ANY QUERIES