Bragg Angles + Thermal Expansion

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SUMMARY

The discussion focuses on calculating the change in Bragg angle (theta) when a crystal's lattice parameter increases due to thermal expansion. Specifically, the lattice parameter 'a' increases by 0.17% when the crystal is heated from 0 to 100 degrees Celsius. The initial Bragg angle is given as 19.3 degrees at 0 degrees Celsius. The participants explore the relationship between the lattice spacing (d) and the Bragg angle using the equation 2dsin(theta) = nλ, but face challenges in determining the new angle without additional information on density or the new lattice spacing.

PREREQUISITES
  • Understanding of Bragg's Law and its application in X-ray diffraction.
  • Knowledge of thermal expansion and its effect on crystal lattice parameters.
  • Familiarity with the concept of lattice spacing (d) in crystallography.
  • Basic algebraic manipulation skills to solve equations involving trigonometric functions.
NEXT STEPS
  • Study the derivation and application of Bragg's Law in X-ray diffraction experiments.
  • Research the effects of thermal expansion on crystal structures and their properties.
  • Learn how to calculate changes in lattice parameters using thermal expansion coefficients.
  • Explore the relationship between density and lattice spacing in crystalline materials.
USEFUL FOR

Students and researchers in materials science, crystallography, and solid-state physics who are interested in the effects of temperature on crystal structures and X-ray diffraction analysis.

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Homework Statement



A crystal is heated from 0 to 100 degrees celsius, its lattice parameter 'a' increases by 0.17% due to thermal expansion. if we observe an x-ray reflection at a bragg angle theta= 19.3 degrees at 0 degrees celsius, by how much will theta change when the sample is heated to 100 degrees C. (don't need to know wavelength or d to solve)

Homework Equations



2dsin(theta) = n[itex]\lambda[/itex]

The Attempt at a Solution



Tried using 1 for d. and just seeing how much it'd change but it didn't come out right.
 
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Should it be d_1*sin(theta_1) = d_2*sin(theta_2) ?
 
Spinnor said:
Should it be d_1*sin(theta_1) = d_2*sin(theta_2) ?

well all we're given is density 1 and theta 1. we don't even know density2 or theta2
 

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