[Wien] [Wien2k Users] The problem of lattice stability

[Ghosh SUDDHASATTWA]

Dear Wien2k users, 

 

When we consider Zr (hcp) in a tetragonal or orthorhombic lattice, 

we have to consider two cases 

1. c/a ratio and b/a ratio 

2. force minimization. 

 

[1] seems to be ok, but I have a querie on [2]. 

We can consider Zr in tetragonal lattice with 1 or more than 1 equivalant
point.

For example, Zr in Delta Prime Plutonium lattice has only one equivalent
atomic position 

 

Zr in Beta-Uranium has five different atomic positions. 

But both these structures are tetragonal. 

Now the difference ENE(Zr, hcp)-ENE(Zr,tetragonal,U) 

and ENE(Zr,hcp)-ENE(Zr,tetragonal,Pu) both would be different (after c/a,
b/a optimization...) 

 

Both are the measure of the lattice stability. 

Which one is right? 

 

 

Suddhasattwa Ghosh

 

 

 

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