Dear,
Making some tests, I observed 2 things: 1- The system takes ~1800 steps to converge the optimization. During ~700 steps the lattice parameters (a, b, c) increase (beta almost isn't changing). It takes some more steps to the beta angle starts to change, while a, b, c decrease. It repeats in all tests I run. 2- Using non-equal k points (2x4x2 and 4x6x4) the lattice parameter values are closer to the experimental than 4x4x4. However, I continue getting values shorter than experimental.
-- SIESTA is supported by the Spanish Research Agency (AEI) and by the European H2020 MaX Centre of Excellence (http://www.max-centre.eu/)
