This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Homework # 1  Solution Problem #1 Simple cubic structure: The distance between nearestneghbor atoms is a . Therefore the radius r of the touching spheres located at lattice sites is / 2 = r a . Since in the simple cubic structure there is one atom in the unit cell, the volume coved by the spheres is 3 3 4 4 3 3 2 π π & ¡ = = ¢ £ ¤ ¥ sc a V r , whereas the total volume of the unit cell is 3 = cell V a . The packing ratio is, therefore, 3 3 4 3 2 0.52 6 π π & ¡ ¢ £ ¤ ¥ = = = ≈ sc sc cell a V p V a . Bcc structure: The distance between nearestneghbor atoms is 3 / 2 a and therefore 3 / 4 = r a . In the bcc structure there are 2 atoms in the conventional unit cell so that the volume coved by the spheres is 3 4 3 2 3 4 π & ¡ = ¢ £ ¢ £ ¤ ¥ bcc a V . The packing ratio is 3 0.68 8 π = = ≈ bcc bcc cell V p V . Fcc structure: The distance between nearestneghbor atoms is 2 / 2 a , so that 2 / 4 = r a . In the fcc structure there are 4 atoms in the conventional unit cell, and therefore the volume coved by the spheres is...
View
Full
Document
This note was uploaded on 09/21/2011 for the course PHYSICS 101 taught by Professor Wormer during the Spring '08 term at Aarhus Universitet.
 Spring '08
 WORMER
 Work

Click to edit the document details