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Embedding energy error

The embedding error in the total energy is computed as

ΔE = EFDE[$\displaystyle \tilde{{\rho}}_{A}^{}$;$\displaystyle \tilde{{\rho}}_{B}^{}$] - EDFT[ρ] (15.12)

where EDFT is the DFT total energy of total system with density ρ(r) . In order to compute ΔE as well as its components, the flag --err-energy must be used. This flag will required also the DFT calculation on the total system. In this case the converged SCF output file must be named output.dscf.

An example of session output for the computation of embedding energy and energy error decomposition[155], when --err-energy flag is present, is the following:

FDE ENERGY (TOTAL SYSTEM):   -200.99720391651 Ha
FDE BINDING ENERGY:                      4.960885 mHa
                                         3.113002 kcal/mol
FDE ENERGY ERROR:                        2.003352 mHa
  coulomb contribution:                 -0.693026 mHa
  nuclear contribution:                 -3.136544 mHa
  exchange-correlation contribution:    -1.156390 mHa
  kinetic contribution:                  6.989320 mHa
where the FDE energy ( EFDE ), the FDE binding energy, the embedding energy error (ΔE ) and the error energy decomposition in its coulomb, nuclear, exchange-correlation and kinetic contributions are reported. This output is present at each FDE iteration.

fde.input option: err-energy=1