Different pieces of software have been developed to solve different aspects of the electronic structure of large nanosystems. All the implemented methods are based on plane wave pseudopotential calculations. The problems can be divided into two parts, one is the construction of the Hamiltonian, another is the method to solve the single particle and many body wave functions based on the Hamiltonian. One can use empirical pseudopotential or charge patching method to construct the Hamiltonian, and Escan or LCBB method to solve the Hamiltonian. One can also do a direct self-consistent density functional calculations using PEtot. The software that implement these different methods are provided in the following links:

1. PEtot (http://hpcrd.lbl.gov/~linwang/PEtot/PEtot.html)
   
2. EPM  (under construction)
3. Charge patching method (under construction)
4. Pescan
5. LCBB (under construction)