CALCULATION METHODS IN COMPUTATIONAL CHEMISTRY

Computational chemistry plays a crucial role in understanding molecular structure, energetics, and chemical properties through theoretical and numerical approaches. This paper reviews the main computational methods used in chemistry, including Molecular Mechanics (MM), semiempirical quantum mechanics, ab initio quantum mechanical methods, and Density Functional Theory (DFT). Molecular Mechanics is based on classical mechanics and is highly efficient for large systems such as proteins and biomolecules, although it cannot describe electronic properties or chemical reactions. Semiempirical methods combine quantum mechanical principles with empirical parameterization, offering a balance between computational efficiency and the ability to model electronic structures. Ab initio methods, which rely purely on quantum mechanics without empirical parameters, provide high accuracy in predicting molecular energies, geometries, and electronic properties, but at a significant computational cost. Density Functional Theory represents a widely used alternative that employs electron density as the fundamental variable, achieving a favorable compromise between accuracy and computational efficiency. The advantages, limitations, and typical applications of each method are discussed to highlight their suitability for different chemical systems and research objectives.