DFT-ulg

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In the DFT-ulg method of Kim et al.[1], the correction term takes the form:

where the first two summations are over all atoms in the unit cell and the third summation is over all translations of the unit cell where the prime indicates that for . denotes the dispersion coefficient for the atom pair , is the distance between atom located in the reference cell and atom in the cell . The DFT-ulg method can be activated by setting IVDW=3. The parameters in the DFT-ulg method (see Ref. [1] for details) that can be modified are listed below.

  • VDW_RADIUS=50.0 : cutoff radius (in ) for pair interactions
  • VDW_S6=0.7012 : global scaling parameter
  • VDW_D=0.6966 : universal correction parameter
  • VDW_C6=[real array] : parameters () for each species defined in the POSCAR file
  • VDW_R0=[real array] : parameters () for each species defined in the POSCAR file
  • LVDW_EWALD=.FALSE. : the lattice summation in expression is computed by means of Ewald's summation (.TRUE. ) or via a real space summation over all atomic pairs within cutoff radius VDW_RADIUS (.FALSE.). (available in VASP.5.3.5 and later)


Mind: The default value of the parameter (0.7012) was determined in conjunction with the PBE GGA functional[1]. Therefore, it is not recommended to use the DFT-ulg dispersion correction with a GGA functional other than PBE, unless is reoptimized.

Related tags and articles

VDW_RADIUS, VDW_S6, VDW_D, VDW_C6, VDW_R0, LVDW_EWALD, IVDW, DFT-D2

References