NUITNS reunites the electronic structure tools QC-Lab, INDO and UVSpect plus the visualization programs Molecular Structure Tracer (MolST) and Theoretical Electron Density Visualizer (TEDViz). Tanks to the fact that these programs share a common syntax in the data input -molecular geometry of the target system- NUITNS facilitates the study and analysis of the calculation.
The molecular structure, i.e., the position of the nuclei and their connecting bonds, may be calculated from the electron density which is derived from the system's wave function. The molecular wave function may be obtained from DFT and ab-initio calculation using the tool QC-Lab.
The study ab-initio of molecules becomes limited by the size of the system: either the number of atoms or the number of basis function and the Hamiltonian quickly overwhelm the computational resources making these theoretical methods technically impractical. The semiempirical methods provide an alternative to the study of large systems. In this realm, NUITNS serves two program: INDO and UVSpect.
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