  In this work we propose a new efficient basis for the electronic structure
problem. The basis is based on the Muffin Tin Orbital (MTO) idea that the
eigenstates of the Khon Sham (KS) Hamiltonian may we be expanded in terms of
eigenstates of the spherically averaged KS Hamiltonian inside the so called
Muffin Tin (MT) spheres and Bessel functions in the interstitial multiplied by
appropriate spherical Harmonics. Here we use the fact that the solution to
problem of finding the ground state electron density is most often done through
an iterative process, where generically on the order of over 20 iterations are
taken till the ground state electron density and energy converges to the lowest
values allowed by the correlation and exchange functional for the fixed form of
the external potential. We use eigenstate information from the previous
convergence iteration to choose the energies of the eigenstates of the
spherically averaged KS Hamiltonian. Furthermore within the Atomic Sphere
Approximation (ASA) the energies of the Bessel functions do not matter as they
are cancelled out. This is an efficient method aimed at studying the electronic
structure of materials with large unit cells especially if they are of close
packed form where ASA is particularly accurate.
