**ATOMIC MATTERS ** and **ATOMIC MATTERS MFA Computation Systems
**are packages of unique tools for describing the physical properties of atomic electron systems with an unclosed electron shell, under interaction with the electrostatic potential of definable symmetry, external magnetic fields, and inter-ionic magnetic interactions (Atomic Matters MFA only). The effect of these interactions, as well as intra-atomic spin-orbit coupling, is the creation of discrete multi-electron eigenstates called Fine Electronic Structure. Taking into consideration the individual population of energy levels of the Fine Electronic Structure at different temperatures permits the temperature dependencies to be defined of many magnetic, electronic, thermodynamic and spectral properties.

Every computer application related to ATOMIC MATTERS has an interface based on a system of hierarchical tabs that contain tools for managing input data and viewing results. The ability to view a variety of data from a single result in sub-grouped tabs makes comparison of the influence of different ions’ charge environments on microscopic physical properties easy with just one mouse click. As well as fine electronic structure with absorption spectra simulations, sub-tabs contain easily comparable visualizations of macroscopic properties. Taking into consideration the individual population of energy levels of the Fine Electronic Structure at different temperatures permits temperature dependencies to be defined of properties such as:

- free energy F(T)
- internal energy U(T)
- magnetic entropy S
_{mag}(T) - magnetic susceptibility calculated in different directions χ
^{i}(T) in a paramagnetic temperature region. - formation of magnetic ordered state (Atomic Matters MFA only)
- localized electronic contribution to specific heat c
_{Schottky}(T) for stable energy levels for structure E_{i }and for magnetic phase transitions (Atomic Matters MFA -only) - structure of discrete electron levels E
_{i}(or E_{i}(T) for magnetization process (Atomic Matters MFA only) and the probability of transitions between them; - magnetic moment and magnetization in ordered state (Atomic Matters MFA only);
- magnetocrystalline anisotropy energy and constants K
_{i}(T) (Atomic Matters MFA only); - spin and orbital contribution to angular momentum of the electron subshell;

ATOMIC MATTERS computation systems, with their rich sets of helpful calculation aids and result comparison tools, simplify the prediction of properties of novel and technologically significant materials.

Constantly striving for maximum simplification of the application interface, we have made it possible to conduct reliable research in the properties of magnetic materials and prediction of properties of solid compounds without knowledge of the complexities associated with the axioms and methodology of quantum mechanics. The application logic can forecast the magnetic, thermal and electron properties for whole isostructural series; therefore, the physical properties of materials whose nature is derived from localized electron states can be predicted. From a practical point of view, the role of electron states for the magnetic, spectral and calorimetric properties of materials containing transition metals, rare earth metals, or uranics, is absolutely fundamental. However, there is much controversy in science when it comes to the selection of an adequate theoretical description of specific groups of chemical compounds in a solid state. While avoiding doctrinal manifestoes, we give you a tool for checking and comparing experimental results for actual materials with the results of theoretical calculations based on accurate quantum mechanical calculations which are in turn based on the formalism of the equivalent operators theory (based on the Wigner-Eckart theorem) under the convention of Stevens' operators. Users have the option to use or eliminate specific approximations, and can define and decide for themselves as to which interactions are negligible and which are not.

All ATOMIC MATTERS software is designed to calculate, simulate and visualize the most relevant properties of materials which are determined by the fine electronic structure of contained ions or atoms. The software is intuitive and productive due to the wealth of interactive tools and the easy portability of data.