1408100045-Nila Huda-Thesaurus of XRD
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Transcript of 1408100045-Nila Huda-Thesaurus of XRD
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T hesaurus of X-Ray D iffractionNila Huda - 1408100045 Kelas A
X-Rays
Electromagnetic radiation of shorter wavelength than ultraviolet radiation
produced by bombardment of atoms by high-quantum-energy particles. The range
of wavelengths is 1011 m to 109 m.
X-Ray Diffraction
A non-destructive analytical technique for identification and quantitative
determination of the various crystalline forms, known as phases.
Powder Diffraction
A scientific technique using X-ray, neutron, or electron diffraction on powder or
microcrystalline samples for structural characterization of materials.
Single-crystal Diffraction
A non-destructive analytical technique which provides detailed information about
the internal lattice of crystalline substances, including unit cell dimensions, bond-
lengths, bond-angles, and details of site-ordering. Directly related is single-crystal
refinement, where the data generated from the X-ray analysis is interpreted and
refined to obtain the crystal structure.
Diffractometer
A measuring instrument for analyzing the structure of a material from the
scattering pattern produced when a beam of radiation or particles (such as X-rays
or neutrons) interacts with it.
Crystalline
Arranged atoms in a regular pattern, and there is as smallest volume element thatby repetition in three dimensions describes the crystal.
Amorphous
Arranged atom in a random way similar to the disorder we find in a liquid. Glasses
are amorphous materials.
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Unit cellthe smallest three dimensional box which can be stacked to describe the 3D lattice
of a solid.
Crystal system
A method of classifying crystalline substances on the basis of their unit cell. There
are seven crystal systems. If the cell is a parallelopiped with sides a, b, and c and if
is the angle between b and c, the angle between a and c, and the angle
between a and b, the systems are: (1) cubic (2) tetragonal (3) rhombic (or
orthorhombic) (4) hexagonal(5) trigonal(6) monoclinic(7) triclinic.
Crystal Lattice
A regular three-dimension distribution (cubic, tetragonal, etc.) of atoms in space.
These are arrange so that they form a series of parallel planes separated from one
another by a distance d, which varies according to the nature of the material. For
any crystal planes exist in a number of different orientations- each with its own
specific d-spacing.
Miller Index
defines the orientation of the plane within the unit cell.
Monochromator
a device used to disperse a broad spectrum of radiation and provide a continuous
calibrated series of electromagnetic energy bands of determinable wavelength orfrequency range.
Detector
Generally a photomultiplier tube that recovers information of interest contained in
a modulated wave.
Diffractogram (diffraction spectrum)
A plot of reflected intensities versus the detector angle 2-THETA or THETA
depending on the goniometer configuration.
Intensity
States the large number of diffraction grating which indicates the crystallinity of a
material. The higher intensity, the more crystallite a material measured
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Angle 2-THETAThe angle of diffraction that indicates phases of crystal of the material measured.
Fingerprint
Evidence for the presence or the identity of a substance that is obtained by
techniques such as spectroscopy, chromatography, or electrophoresis.
Broadening of spectral lines
A widening of spectral lines by collision or pressure broadening, or possibly by
Doppler effect.
Half-width
Half the width of a spectrum line (or in some cases the full width) measured at half
its height.
Reference material
A material or substance whose properties are sufficiently well established to be
used in calibrating an apparatus, assessing a measurement method, or assigning
values to other materials.
Bragg's Law
Refers to the simple equation: n= 2d sin that explain why the cleavage faces of
crystals appear to reflect X-ray beams at certain angles of incidence (, ). The
variable d is the distance between atomic layers in a crystal, and the variablelambda is the wavelength of the incident X-ray beam; n is an integer.
Scherrers Formula
The formula that explaine how to know crystallite thickness (t) from the peak of
diffraction spectrum by this simple equation: t = 0,89 / B cos. B is full width at
half max of the peak.
Rietveld refinement
A technique used in the characterisation of crystalline materials. The neutron and
x-ray diffraction of powder samples results in a pattern characterised by reflections
(peaks in intensity) at certain positions. The height, width and position of these
reflections can be used to determine many aspects of the materials structure.