An atomic state in which two spin angular momenta of electrons cancel each other, resulting in zero net spin, is called a singlet. If the angular momenta combine to give a total non-zero spin, then that state is called a triplet. A triplet state usually has lower, sometimes substantially lower, energy than a singlet. Importantly […]
Electrons do not move around nuclei in defined curved orbits. Our current understanding of how electrons are to be found in atoms and molecules is based on clouds of probability called orbitals as it is not possible to give a definite path for an electron. Thus, an orbital is a region in which an electron […]
Cromophores are generally groups of atoms having delocalized electrons. Covalent assemblies of conjugated organic chromophores provide the opportunity to engineer new excited states with novel properties. A team of researchers has now used a novel cage architecture for creating them. The properties of organic electronic materials being determined by the interactions between their conjugated subunits […]
Aromaticity is a property of cyclic (ring-shaped), planar (flat) structures with π bonds in resonance (those containing delocalized electrons) that gives increased stability compared to other geometric or connective arrangements with the same set of atoms. Aromatic rings are very stable and do not break apart easily. An aromatic ring contains a set of covalently […]
Deoxyribonucleic acid (DNA) is the genetic material of most living organisms, being a major constituent of the chromosomes within the cell nucleus and playing a central role in the determination of hereditary characteristics by controlling protein synthesis in cells. DNA is, thus, a nucleic acid composed of two chains of nucleotides in which there is […]
Molecules when excited from their ground state (S 0 ) to their lowest electronically excited states often change their electronic structure considerably, which impacts on a range of important molecular properties. For example, the reactivity of a molecule in its excited state often differs markedly from that in its S 0 state. Also, the charge […]
During the last decades, the electronics industry has been very successful in pushing forward the advancement of electronic building blocks, but the limit of silicon-based electronic devices especially in terms of miniaturization are almost reached. There are many ideas how to overcome this problem, for example, by adding functionality based on approaches originating from molecular […]
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 […]