The potential energy per unit of charge; the difference in electrical potential between two points is the voltage (V).

An electrode is a charged wire or plate. An anode is a positively charged electrode and a cathode is a negatively charged electrode. Charged particles are attracted to the electrode of opposite charge.

Electron tunneling is a quantum mechanical property that occurs because electrons behave as waves of energy and are thus capable of passing through an energy barrier that would not be possible in classical mechanics. In scanning tunneling microscopy (STM), the tip and sample wave functions overlap so that when a bias voltage is applied, there is some finite probability of finding the electron on the other side of the energy barrier. Depending upon the direction of the bias voltage in STM, an electron may jump the gap or ‘tunnel’ across the barrier from tip to sample or from sample to tip.

Electronegativity (electron affinity) is the ability for an atom to attract electrons. The original definition was specific to atoms, but it is often applied to functional groups, although reference to the dipole moment, polarity, and/or Lewis acid/base character may be more appropriate to describe the attraction of electrons within a particular molecule or bonding environment.

A constraint imposed on classical calculations or simulations of atomic structures in which the model system contains no net electric charge.

See podoconiosis.

An obsolete term for allophane associated with lignite from Friesdorf, Germany.

See air classification.

See deposits, eluvial.

In crystal nucleation theory, an incipient and metastable particle with a size smaller than a critical radius.
See critical radius