Exercise 2.1-2

Do the Math for the Formation Entropy

Do the Math needed for going from the first to the second formula:
First formula:
 
F  =  – kT · lnZ  =  kT ·

i
( i
4π · kT
 +  ln ( 1 –  exp – i
2π · kT
) )
 
  Second formula:
 
S  =  k ·

i
( – ln ( 1  –  exp  i
2π · kT
)  + 
   i
2π · kT
  

   exp  ( i
2π · kT
  –  1 )   
)
 
Now, using the approximations referred to, derive the Final formula
 
SF  = k ·

i
  ln  ωi
ω'i
 
Discuss the quality of the approximations
(Hint: Use some real numbers or order of magnitudes for e.g. Debye temperatures, vacancy concentrations etc.)
   
 
 

Link to the Solution

 

To index To index

go to 2.1.1 Simple Vacancies and Interstitials

go to Solution to Exercise 1.3

© H. Föll