Modeling structure and properties of molecules and materials based on their electronic structure is one of the principal consumers of computer resources (time, memory and storage). The known attempts to improve the efficiency of such a modeling stumble upon the enormous diversity of types of structures and behaviors. Even worse, this diversity is not reflected in the dominating paradigm of molecular/material modeling, which can be chracterized as na ïve monism: it is believed that everything must be calculated by the same, possibly most precise available theory.
This, of course, leads to a deadlock. Truly scientific approach is based on a thorough analysis of physics governing the observed diversity. We followed this route and built a series of methods targeted upon specific classes of molecules/materials: inorganics with open d-shells, organics featuring local two-center bonds and conjugated π-systems. The approach is described in .
The experience gained through these studies led to a new vision of semi-empirism : selecting the electronic wave function of a system as a product of observable electronic groups (chromophores) present in it. This requires a development of a library of objects representing different types of chromophores to be freely combinable to represent an arbitrary system so that its respective parts are modeled by the most efficient method suitable for the specific type of the chromophore and taking into account interactions between them. This is done within our project library Cartesius .
We developed a series of targeted numeric tools based on this library: LiquIon – a tool for modeling thermodynamical properties of ionic liquids  and adamas – a tool targeted on description of carbon allotropes  and providing their crystalline structures, relative energies and elastic properties. atoms – implements calculations of atomic properties in exponential bases . GoGreenGo – local perturbations of periodic systems: chemisorption and point defects . jakontos – Effective Hamiltonian Crystal Field for periodic systems with transition and rare-earth elements . They available through the NetLaboratory system .