DFT-NL¶
Section author: Holger Kruse
Non-local (NL), density based correlation energy from the VV10 kernel can be added to arbitrary functionals.
For pre-defined functionals (see Functional overview in this Table ) it is sufficient to add -NL to the functional name:
1 | energy('b3lyp-nl')
|
Modification of the parameters b and C is done setting DFT_VV10_B and DFT_VV10_C. The C is usually left unchanged and the originally proposed value of C=0.0093 is used.
Adding DFT_VV10_B to any functional activates the calculation of the VV10 kernel. A BLYP-NL calculation can be set as follows:
1 2 | set DFT_VV10_B 4.0
energy('blyp')
|
The default C parameter will be used.
Similar to DFT_DISPERSION_PARAMETERS the tuple NL_DISPERSION_PARAMETERS can used:
1 2 | set NL_DISPERSION_PARAMTERS [4.0]
energy('blyp')
|
which is equivalent to the example above.
Further examples can be found in the respective regression test
post-SCF time savings¶
Substantial time-savings for energy calculations are available by evaluating the VV10 kernel only at the converged electron density, i.e. in a post-SCF fashion. The deviations from the fully self-consistent treatment are usually minimal. To activate this set DFT_VV10_POSTSCF to true.
