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The Functional Density Theory propose an alternative method to calculate electronic properties, in the fundamental state, for molecular system with many-electrons.

In this formalism the variational parameter is a scalar function (electron density  ), which is electron position dependent. The DVM - Discrete Variational Method is a self-consistent variational first-principal method, based on a local density theory to define exchange and electronic correlation potential. The mono-electronic wave function of the cluster is represented by a linear combination of the atomic orbital (LCAO). In case of crystals is necessary to introduce a embedded region to represent the rest of the crystal.

Self-consistent DV method can be summarized in following scheme;

a) The electronic density function  is defined by (17) and it is calculated considering all atoms in system .

where  are radial eigenfunctions used to construct the LCAO base and the  represent the amplitude of the interaction between the elements i and j.

b) The Coulomb  , exchange  and self-correlation  contribution to the total atomic potential is calculated.

c) Create the matrix  and the kinetic energy  to evaluate the Hamiltonian operator

d) Solve the secular equation to obtain information about the mono-electronic spectrum and to create the new set of  coefficients;

e) Calculate the matrix elements  to define the charge  .

f) Go back to a) until the convergency criteria is reached within a desired precision.