ABSTRACT
In numerical simulations, based on frozen-density embedding theory, the independent variables describing the total system are the embedded wave function (ΨA) and the density representing the environment. Due to inhomogeneity of the non-electrostatic component of the total energy: ), the expectation value of the embedding potential is not equal to the corresponding component of the total energy. The differences are evaluated using local and semi-local approximations for the functional EnadxcT[ρA, ρB] in two model systems representing embedded species weakly interacting with the environment. It is found that ΔnadxcT is typically one order of magnitude smaller than EnadxcT[ρA, ρB] and decreases with the overlap between and . The kinetic- and exchange-correlation contributions to ΔnadxcT cancel partially reducing its magnitude to mHartrees. Compared to local approximation for EnadxcT[ρA, ρB], the inhomogeneity is more pronounced in semi-local functionals.
Acknowledgements
The authors would like to dedicate this work to Professor Andreas Savin on the occasion of his 65th birthday. Francesco Aquilante gratefully acknowledges support from the FIRB “PROGRAMMA FUTURO IN RICERCA” RBFR1248UI by the Italian ‘Ministero dell’Istruzione, dell’Università e della Ricerca’ (MIUR).
Disclosure statement
No potential conflict of interest was reported by the authors.