Here are a few things that might help.

For a single atom, you don't need such a large unit cell, something like 10Å×10Å×10Å should be enough. Also, use ibrav=1 for a cubic lattice (you just need a box with the atom in it). As for K-mesh, use 1x1x1 since there is no periodicity to sample. Furthermore, there are four 'starting_magnetization(i)' why? ~keep just one (choose accordingly). Your values for ecutrho and ecutwfc are very high. Consider reducing them to something like 240 Ry and 40 Ry (4×ecutwfc for ecutrho is standard). Finally, ion_dynamics = 'bfgs' is unnecessary for a single atom. Instead, use calculation ='scf' or 'relax'.

These changes will very likely resolve your convergence issue.

Hope that helps,

Rgds

Hello Mustafa Kaya

I agree with everything Gabriel Vinicius suggested. Also, I suggest that you put your atom in the center of your cell, so Quantum Espresso can recognize symmetry, making calculation much faster. I made a calculation with a single Vanadium atom, using the suggested corrections, using the same pseudopotential, and I am convinced you had problems with that 4 lines of 'starting_magnetization(i)'. It's not only unnecessary, but prevented your magnetization to converge. For a single Vanadium atom, using even different pseudopotentials, I get a magnetization of 5 Bohr mag/cell, which your calculation didn't reach.

Try this input I just did, you won't have trouble with it. Remind to change your pseudopotential and the pseudoponteial file location.

Best regards

Ricardo Tadeu

In the event that a pseudo potential base set has not been utilised, it is necessary to employ one.

Should the problem persist, a key such as pseudo=read should be utilised.

Thanks for your help, I will try it as soon as possible