From: tommi.hoynalanmaa@gmail.com   
      
   I'm trying to minimize the energies of hydrogen molecule and lithium   
   hydride molecule with the L-BFGS method and HGH pseudopotential [1].   
   Hydrogen molecule works fine but lithium hydride does not. The forces   
   exerted on the nuclei are approximately zero (order of magnitude 10^{-8}   
   Ha/Bohr) for H2. When I minimized the energy of LiH manually and   
   computed the forces exerted on the Li core (nucleus and 1s orbitals) and   
   H nucleus the forces were -9.696*10^{-2} Ha/Bohr for Li and   
   -1.126*10^{-3} Ha/Bohr for H.   
      
   Should the forces be zero for the equilibrium state even though the   
   forces are internal to the system?   
      
   Assuming that the computations are otherwise correct could the error in   
   the  computation of the force related to the nonlocal HGH   
   pseudopotential of Li core affect the computed force exerted on the H   
   nucleus?   
      
   [1] Hartwigsen, Goedecker, and Hutter. Relativistic separable dual-space   
   Gaussian Pseudopotentials from H to Rn. arXiv:cond-mat/9803286   
   [cond-mat.soft]   
      
        - Tommi Höynälänmaa   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)