Category archives: Quantum chemistry

Molecular spintronics is an emerging field that combines ferromagnetic materials with organic or metal–organic semiconductors. It benefits from the unique and exceptional properties of organic molecules, which go beyond inorganic ones. The strong response of many organic molecules to electrical, optical, ferromagnetic or antiferromagnetic stimuli bring new potential functionalities to the spintronic device. An effective […]

Light emission (fluorescence or phosphorescence) in organic molecules, in the vast majority of cases, proceeds from the lowest energy excited state irrespective of the excitation energy used. This is known as the Kasha’s rule, which states that most of the molecules are emissive from the lowest energy, same (ground state) spin multiplicity, S1 excited state […]

Nonlinear optics is concerned with the optical properties of matter subjected to intense electromagnetic fields. For nonlinearity to manifest itself, the external field should not be negligible compared to the internal fields of atoms and molecules of which the matter consists. Lasers are capable of generating external fields sufficiently intense for nonlinearity to occur. Actually […]

Today, computational chemistry helps the experimental chemist understand experimental data, explore reaction mechanisms or predict completely new molecules. There is no doubt that understanding at the molecular level will ultimately lead to an ab initio process design. Thus, the solution of the quantum mechanical many-electron problem is one of the central problems of physics and […]

If a nucleus has a non-zero spin, it behaves as a small magnet. Therefore, in an external magnetic field, the nuclear magnetic moment vector precesses about the field direction but only certain orientations are allowed by quantum rules. Thus, for hydrogen (spin 1/2) there are two possible states in the presence of a field, each […]

Topological materials have special universal properties, which are protected against perturbations. Such properties are theoretically described by topology, a branch of mathematics concerned with the properties of geometrical objects that are unchanged by continuous deformations. Topological materials behave like an ordinary insulator in the bulk but have conducting states on their boundaries, i.e., edges or […]

We usually take for granted that aromaticity is something that belongs to the ground state of a molecule; but the fact is that nothing forbids aromaticity appearing in an excited state. In the same way that molecular properties are largely affected by the ground-state aromaticity, excited-state aromaticity can guide the understanding of excited-state processes, the […]

One of the ultimate goals in surface science is to comprehend the fundamental processes that make that surface reactions need less than a picosecond (10-12 s) to occur. This means understanding what is happening at the scale of femtoseconds, that is, measuring things that take some tens or hundreds of 10-15 seconds to occur. To […]

Adsorption commonly is understood as the reversible binding of molecules and atoms from the gaseous or liquid phase on surfaces, mostly of highly porous adsorbent media. In chemisorption a single layer of molecules, atoms or ions is attached to the adsorbent surface by chemical bonds; in physisorption only van der Waals forces are involved. The […]

Modern organic industrial chemistry started when William Henry Perkin serendipitously synthesized mauveine in 1856 while he was attempting the total synthesis of quinine. Since then, thousands of new organic products have been created in the laboratory for industrial purposes. Among them, in 1913, an orange-red pigment was found, first known as Vat Orange 3 dye […]