# How to do a Sampling on the boundary of Brillouin zone in VASP

I use VASP to do my DFT calculation. I have to do a self consistent calculation to generate my CHGCAR. I want to ask is there anyway to write the KPOINTS file to generate K-meshing grid which can exactly lying in $$(\frac{\pi}{a} , \frac{\pi}{a}, \frac{\pi}{a})$$ point in square Brillouin zone boundary? As I used Monkhost-Pack grid, which can only guarantee that your point grid can be located at Gamma point.

• In principle it is possible to add the k-points that you want explicitly in VASP, is this what you are asking, or are you asking more generally about sampling k-point grids (irrespective of VASP)? May 9 at 7:37
• @ProfM Yes. But when I use this method It will give an error as follow: "error in ibzkpt_hf: two k-point are equivalent". But I have check that no K-point are equivalent in my file except the TRIM in boundary which connected by reciprocal lattice vector and differ by a sign. May 9 at 10:19
• I would say that two points separated by a reciprocal lattice vector are equivalent; why do you want to include both? May 9 at 10:36
• @ProfM Because I turned off the symmetry TAG in the INCAR file, and the KPOINT grid should be symmetry in the Brillouin zone. I try to fit run VASP2Wannier90 that's why I want to include the high symmetry point in my file. May 9 at 10:43
• If you turn off the symmetry with ISYM = -1, the point group symmetry found for your structure is not imposed on the Kohn–Sham orbitals. However, there is no way to turn off periodic boundary conditions in VASP! So $\vec{k}$ points separated by reciprocal lattice vectors are always equivalent. May 22 at 1:28