I am new using your FLEUR code. I would like to know how to compute the matrix element associated to the P operator. In other world, providing to states |n,k> and |n',k> associated with bands n and n' for a given k vector, how to get the matrix <n',k|p_j|n,k> for the three dimensions j. I did not see in the documenttaion how to access, if calculated, this quantity. Also I would like to know if the matrix element <n',k|dVKS/dj|n,k> with VKS the Kohn-Sham potential of the DFT, can be computed.
Last do we agree that since no pseudo potentials are used, VKS is a local operator.

Thank you in advance,
Looking forword to reading you