Quantum chemistry is a field of chemistry whose primary focus is on the application of quantum mechanics in physical models and experiments in chemical systems. In the late 17th century, Newton discovered the laws of classical mechanics for moving microscopic objects. In the early twentieth century, physicists realized that the motion of small particles, such as the nuclei of atoms and electrons, could not be justified by the laws of classical mechanics, and therefore the motion of these particles was justified by a set of rules called quantum mechanics. Quantum Chemistry uses the laws of quantum mechanics in chemistry. The effects of quantum chemistry are felt in all branches of chemistry.
Chemical physicists use quantum chemistry (along with statistical thermodynamics) to calculate the thermodynamic properties of gases, explain the molecular spectra, and experimentally obtain some of the properties of molecules (such as bond length and angle, bipolar moment, energy difference in different formulations). Chemists use this science to determine the stability of molecules, to calculate the mean of reactions, to investigate the mechanism of reactions, to predict the aromatic properties of compounds, and to justify NMR spectra. Cleansing chemists widely use spectroscopy methods. The frequencies and intensities of spectral lines can be easily understood and justified by quantum chemistry. Other uses for them include explaining the mechanism of electrochemical reactions. Mineral chemists use ligand field theory, and approximate methods of quantum mechanics to justify the properties and electron transfers in intermediate metal complexes.
Although the large size of biomolecules makes it difficult for them to use quantum computing, biochemistry is increasingly being used by quantum studies. Especially in the field of the link between enzymes and substrates and the solubility of biological molecules.