Dear team, I am having a problem reproducing the lattice constant of Vanadium as reported in the paper:
http://onlinelibrary.wiley.com/doi/10.1002/qua.10402/abstract I followed the recipe in the paper to create the PS file: for s, p, d orbitals, setting the core radii to be 2.35, 2.7, 2.35. Then we set the non-linear core correction radius to 0.8. Below is the ATOM input file I created for that: #--------------------------------------------------------------------------------------------------- pe tm2 V pbs 0.000 0.000 0.000 0.000 0.000 0.000 5 4 4 0 2.000 0.000 #4s 4 1 0.000 0.000 #4p 3 2 3.000 0.000 #3d 4 3 0.000 0.000 #4f 2.35000 2.70000 2.35000 2.50000 1.00000 0.80000 #--------------------------------------------------------------------------------------------------- Now, my problem is: the authors of the above paper say that the lattice constant of bulk vanadium, according to SIESTA calculations that they have performed, is 3.02 Ang. However, using the PS file generated from the above input file, I get wrong lattice constants! If I run using pbs (PBE with spin), the lattice constant is close to 3.25 Ang. If I run with pb (PBE without spin), the lattice constant is close to 2.5 Ang! The way I calculate the lattice constant: I vary the lattice constant and compute the total energy in a single DFT run, then plot the energies versus the lattice constant. Can anyone help? Sherif
