Geometric optimization and Temperature

Message

saran6187 · #1 Post by **saran6187** » Mon Sep 10, 2012 4:46 pm

Hi,
I am doing geometric optimization at zero temperature to get the lattice constant, relaxed structure and DOS of the system.
I would like to have the effect of temperature on the above. I am not sure how to combine both (geometric optimization and molecular dynamics) to get the effect of temperature on lattice constant and Density of States.

Any help/suggestion for the above is highly appreciated !

Thanks a lot !

Best regards,
Saran

vistawanted · #2 Post by **vistawanted** » Tue Sep 11, 2012 8:23 am

Your calculations (DOS, relaxation...) are based on DFT, meaning Born-Oppenheimer approx, which is of electronic scale.
Molecular dynamics (MD), even it can contains temperature term, is of atomic scale.
Although there is a method so-call Ab-initio-MD, it cannot provide the DOS result at finite temperature.
With pure Ab-initio, you can use the quasi-harmonic approximation (QHA) method to find the temperature effect on lattice parameters. Of course, the finite temperature DOS is also not provided.

saran6187 · #3 Post by **saran6187** » Tue Sep 11, 2012 8:48 pm

Hi,
Thanks for the information. I would like to know if there is a way to get the DOS incorporating the temperature effects using VASP ?