Chapter 5: Crystal Imperfections

Example 5.1, page no-130

In [2]:
# Average distance between dislocations

import math 
#variable Declarat
a=3.615*10**-10            # interatomic distance of copper
t_ang=0.75                 # angle of tilting
h=1.0                      # Miller indices wrt X-axis
k=1.0                      # Miller indices wrt Y-axis
l=0.0                      # Miller indices wrt Z-axis

#calculation
d_110=a/math.sqrt(h**2+k**2+l**2)
D=d_110/math.tan(t_ang*math.pi/(180*2))

#Result
print('The average distance between the dislocations is %.3f A°'%(D*10**6))

The average distance between the dislocations is 0.039 A°

Example 5.2, page no-130

In [1]:
# Schottky defects per unit cell

import math
#variable declaration
lp=4.0185*10**-10          # lattice parameter
dens=4285.0                # Density of CsCl in kg/m^3
avg=6.022*10**26           # Avogadro's number
wt_cs=132.9                # Molecular weight of Cs
wt_cl=35.5                 # Molecular weight of Cl

#calculations
N=(dens*avg*lp**3)/(wt_cs+wt_cl)
sd=(1-N)*100.0/1.0

#Result
print('The number of Schottky defects per unit cell = %.3f%%'%sd)

The number of Schottky defects per unit cell = 0.565%