Applications of Quantum Chemistry in Molecular Spectroscopy and Reactivity

Quantum chemistry is critical in the explanation of molecular structures, spectroscopy, and chemical reactivity through the application of quantum mechanical principles to chemical systems. This review talks about how quantum chemistry is used in different types of molecular spectroscopy, like UV-Vis, infrared (IR), Raman, and nuclear magnetic resonance (NMR) spectroscopy, where quantum calculations help predict changes in electrons, vibrations, and spin interactions. Also, the research considers quantum chemistry's role in chemical reactivity by charting possible energy surfaces (PES), locating transition states, and minimizing reaction paths with computational techniques such as Density Functional Theory (DFT), ab initio methodologies, and Quantum Molecular Dynamics (QMD). The marriage of quantum chemistry and experimental methodologies has greatly facilitated drug discovery research, catalysis research, and materials science research to the extent that innovations in energy storage and sustainable chemistry have emerged. Despite the achievements, challenges in the form of computational expense, accuracy limitations of electron correlation models, and improvement of hybrid functionals persist. Improving computational efficiency, integrating quantum chemistry with machine learning, and further development of its applications in quantum computing for more accurate predictive modelling are some directions that future research must pursue. This review emphasizes the revolutionary effect of quantum chemistry on contemporary scientific achievements and its future scope in spectroscopic studies and reactivity research.