HFSingularity

HFSingularity

Section Hamiltonian::XC
Type integer
Default general

(Experimental) This variable selects the method used for the treatment of the singularity of the Coulomb potential in Hatree-Fock and hybrid-functional DFT calculations. This shoulbe be only applied for periodic systems and is only used for FFT kernels of the Poisson solvers.

Options:

• none:
  The singularity is replaced by zero.
  
• general:
  The general treatment of the singularity, as described in Carrier et al, PRB 75 205126 (2007). This is the default option
  
• fcc:
  The treatment of the singulariy as described in Gygi and Baldereschi, PRB 34, 4405 (1986). This is formally valid for cubic systems only.
  
• spherical_bz:
  The divergence in q=0 is treated analytically assuming a spherical Brillouin zone
  

 call parse_variable(namespace, 'HFSingularity', default, this%coulomb_singularity)