Quantum potential chemistry

Bohmian theory, also known as the causal interpretation of quantum theory, assumes that classical and non-classical concepts merge in the quantum limi t, defined as the point where the quantum potential becomes insignificant. In this formalism, particle properties are associated with the wavefronts o f wave mechanics, and concepts such as trajectory, space coordinate, veloci ty and angular momentum acquire concrete meaning, also within quantum theor y. The difference between classical and quantum systems relates to the emer gence of the concepts quantum potential and quantum torque that enrich the interpretation by supplementing the classical ideas of kinetic energy and a ngular momentum, in the science of chemistry there are many ideas such as e lectronegativity, valence state, chemical potential and molecular structure that appear to have both classical and quantum attributes. It is logical t hat the next step is to look for a reinterpretation of chemistry in terms o f Bohmian theory. An immediate result is the plausible account of the stabi lity of matter in terms of stationary states of zero kinetic energy. This r esult explains, in turn, the nature of the valence state defined as the sta te of atomic activation due to environmental factors, at which an electron decouples from the atomic core. The decoupled electron only has quantum pot ential energy which allows non-local interaction with an activated neighbou rhood. The formation of molecules results from the disruption of the non-lo cal quantum potential field. Compared with the interaction within the molec ule, interaction with distant objects becomes rather feeble as the total ho listic wave function of the activated medium partitions into a product stat e representing distinct molecules. The quantum potential energy supersedes the classical concepts of electronegativity and chemical potential, whereby chemical reactivity and equilibrium conditions can in principle be quantif ied. Molecular stationary states, like the atomic, are states of close-to-z ero kinetic energy and angular momentum of motion. The guiding principle th at promotes chemical binding is the quenching of angular momentum. As a vec tor quantity, orbital angular momentum of motion responds to its three-dime nsional environment and dictates specific conformation of molecules in term s of nuclear positions. Optical activity is the result of residual angular momentum that cannot quench in chiral molecules. The resultant orbital magn etic moment interacts with the polarized photon field. In some cases the qu enching of angular momentum depends critically on the antiparallel alignmen t of planes of circulating charge and for this reason the resultant structu re resists twisting out of this plane to constitute a barrier to rotation. Many traditional concepts of theoretical chemistry are incompatible with th e causal model. This includes the concept of re-bonding that often requires the promotion of an s-electron into a p-state for which it lacks the neces sary angular momentum. Some predicted structures resemble their classical a nalogues, but many others have unexpected non-classical bonding patterns.