DFtotal

Dftotal is a term found in some computational chemistry and physics software as a label for the total energy contribution associated with density functional theory (DFT) calculations. Its exact meaning is not universal and depends on the program, the input options, and the conventions used by the developers. In many cases dftotal refers to the energy that results directly from the DFT formalism, as opposed to additional energy terms that may be added later in a workflow.

In the framework of Kohn–Sham DFT, the electronic energy comprises several components: the kinetic energy of the noninteracting electrons, the external potential energy due to nuclei, the classical Hartree (electrostatic) energy from electron–electron repulsion, and the exchange–correlation energy that accounts for many-body effects. Depending on the software and settings, dftotal may represent this electronic energy alone or the full energy used to characterize the system. Some implementations separate dftotal from nuclear-nuclear repulsion or from post-DFT corrections, so the exact aggregation can vary.

Practically, dftotal is typically reported in the program’s output or log files and is usually given in a specific energy unit, commonly Hartrees or electronvolts. Users should verify whether the value includes additional terms such as dispersion corrections, zero-point energy, solvent effects, or two-body interactions that may be included in a broader total energy calculation. Because naming conventions differ, consulting the software’s documentation or help files is advisable when interpreting dftotal in a given calculation.