dear siesta users i need to calculate the bulk modulus in order to test the pseudopotential for technetium. Tc is found in hexagonal structure, so along with varying the lattice constant, do i need to change 'c' as well? is it enough to use md.variable cell? how will i know that cell geometry remains hexagonal? should i fix the atomic positions? Is it all right if i test the pseudo for fcc structure instead and compare the results with available theoretical results.
