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Xrays passed through a crystal will be bent at various angles. The process by which the bending occurs is called diffraction. The angle at which Xrays are diffracted is dependent upon the distance between adjacent layers of atoms or ions. Xrays that strike adjacent layers can add their energies constructively when they are inphase. This produces dark dots on the detector plate . By rotating the sample, ciruclar patterns of diffracted Xrays are created . The distance “R” between the center of the ring and a dark dots is used to calculateXrays passed through a crystal will be bent at various angles. The process by which the bending occurs is called diffraction. The angle at which Xrays are diffracted is dependent upon the distance between adjacent layers of atoms or ions. Xrays that strike adjacent layers can add their energies constructively when they are inphase. This produces dark dots on the detector plate . By rotating the sample, ciruclar patterns of diffracted Xrays are created . The distance “R” between the center of the ring and a dark dots is used to calculateXrays passed through a crystal will be bent at various angles. The process by which the bending occurs is called diffraction. The angle at which Xrays are diffracted is dependent upon the distance between adjacent layers of atoms or ions. Xrays that strike adjacent layers can add their energies constructively when they are inphase. This produces dark dots on the detector plate . By rotating the sample, ciruclar patterns of diffracted Xrays are created . The distance “R” between the center of the ring and a dark dots is used to calculate
XRD METHOD I DEFINITION AND PRINCIPLE II SOME APPLICATIONS I DEFINTION AND PRINCIPLE What is X-ray diffraction? X-rays passed through a crystal will be bent at various angles The process by which the bending occurs is called diffraction The angle at which Xrays are diffracted is dependent upon the distance between adjacent layers of atoms or ions X-rays that strike adjacent layers can add their energies constructively when they are in-phase This produces dark dots on the detector plate By rotating the sample, ciruclar patterns of diffracted X-rays are created The distance “R” between the center of the ring and a dark dots is used to calculate th distance between adjacent layers in the crystal Bragg’s Law II SOME APPLICATIONS Distribution of atoms in the unit cell, i.e the crystal structure, either to verify that the material has one of the already known types of crystal structures or to solve it from first principle Phase composition of a material, including both qualitative and quantitative analyses coupled with searches of various databases XRD is a useful technique to determine the distance between layers of atoms or ions in crystalline materials The X-ray pattern that is produced is unique to the crystal and can be used to identify the components of the crystal and its crystal structure The information from the length of a crystal’s unit cell can be used to detremine the density of compounds Measuring the length of crystal’s unit cell Phase identification and analysis Each powder diffreaction pattern is characterized y a unique distribution of both positions and intensities of Bragg peak, where peak positions are defined by the unit cell dimensions and reflection intensities are stablished by the distribution of atoms in the unit cell of every crystalline phase present in the sample Thus, every individual crystalline compound has its own “fingerprint”, which enables the utilization of powder diffraction data in phase identification XRD – LaMnO3 (STANDARD SAMPLE) XRD – THE SYNTHESIZED SAMPLE The column containing full widths at haft maximum of the observed Bragg peak is a useful tool in deciding whether or not the final differences between the observed and calculated Bragg angles are satisfactory Quantitative analysis Quantitative phase analysis is used to determine the concentration of verious phases that are present in a mixture after the identity of every phase has been established This equation makes use of the fact that the scattered intensity is proportional to the amount of a particular phase THE END THANK YOU FOR YOUR ATTENTION ... which enables the utilization of powder diffraction data in phase identification XRD – LaMnO3 (STANDARD SAMPLE) XRD – THE SYNTHESIZED SAMPLE The column containing full widths at haft maximum of... including both qualitative and quantitative analyses coupled with searches of various databases XRD is a useful technique to determine the distance between layers of atoms or ions in crystalline