[Wien] Differences in the hcp and fcc stabilities of zirconium

[Ghosh SUDDHASATTWA]

Dear Wien2k users, 

Initially, I did the total energy calculation of hcp Zirconium with c/a
optimization. 

I had updated the command in the optimize.job 

Run_lapw -cc 0.0001 -ec 0.0001 -so 

 

I got a fairly good plot of energy vs c/a. The equilibrium energy with
optimized c/a was -7198.44622432 Ry/atom 

I did the same job for fcc zirconium (metastable state) 

I did the volume optimization with the command in the optimize.job

Run_lapw -cc 0.0001 -ec 0.0001 

Without spin orbit coupling 

The equilibrium energy was -7198.427610 Ry/atom 

If we take the difference, it comes out to be -0.01861432 Ry/atom. 

If we convert to kJ/mol, it comes out to be -24.435 kJ/mol (multiply Ry/atom
by 13.6 eV and 96.48846 kJ/mol) 

 

The difference seems to be very large. The difference is reported to be
-3.69 eV/atom by VASP. (PAW-GGA) {CALPHAD, 28 (2004) 78-90}

Can anybody tell me as to why I am getting such a high value of the lattice
stability? 

Is it because of the incorporation of spin orbit coupling? 

I had initially used the in1new switch to get the best linearization
energies for both the cases, still I am getting such a high value

Any suggestions?

 

Suddhasattwa 

 

 

 

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