Quantum Theory Vocabulary

Subshells

electrons in multi-electron atoms are grouped according to the value of l.

Shells

electrons in multi-electron atoms are grouped according to the value on n.

Phosphorescent

have metastable states (long-lived) that emit light seconds or minutes after absorption of light.

Holograms

images with a 3-dimensional quality, formed by interference of laser light).

Spin Quantum Number

is a value (of 1/2) that describes the angular momentum of an electron. An electron spins around an axis and has both angular momentum and orbital angular momentum.

Principal Quantum Number

represents the relative overall energy of each orbital, and the energy of each orbital increases as the distance from the nucleus increases. The sets of orbitals with the same n value are often referred to as electron shells or energy levels.

Principle of Complementarity

tenet that a complete knowledge of phenomena on atomic dimensions requires a description of both wave and particle properties.

Pauli Exclusion Principle

the arrangement of electrons in multi-electron atoms which states that no two electrons can occupy the same quantum state-they cannot have the same set of quantum numbers.

Quantum Mechanics

the branch of mechanics that deals with the mathematical description of the motion and interaction of subatomic particles, incorporating the concepts of quantization of energy, wave-particle duality, the uncertainty principle, and the correspondence principle.

Wave-particle duality

the concept that every elementary particle or quantic entity may be partly described in terms not only of particles, but also of waves.

Pair Production

the conversion of a radiation quantum into an electron and a positron.

Ground State

the lowest energy state of an atom or other particle.

Quanta

the minimum amount of any physical entity involved in an interaction.

Photoelectric Effect

the observation that many metals emit electrons when light shines upon them.

Zeeman Effect

the splitting of the spectrum line into several components by the application of a magnetic field.

Selection Rule

transitions between states obey this rule and are far more probable than other so-called "forbidden" transitions.

Uncertainty Principle

dictates that, at the miniscule level of quantum mechanics, it becomes impossible to measure a particle's exact location with any degree of precision.

Blackbody

refers to an opaque object that emits thermal radiation

Metastable

(long-lived) states that emit light seconds or minutes after absorption of light.

Magnetic Quantum Number

Specifies the orientation in space of an orbital of a given energy (n) and shape (l). This number divides the subshell into individual orbitals which hold the electrons; there are 2l+1 orbitals in each subshell.

Line Spectra

a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies.

Quantum Number

a number that occurs in the theoretical expression for the value of some quantized property of a subatomic particle, atom, or molecule and can only have certain integral or half-integral values.

Orbital Quantum Number

a quantum number for an atomic orbital that determines its orbital angular momentum and describes the shape of the orbital.

Bohr Theory

a theory of the structure of atoms stating that electrons revolve in discrete orbits around a positively charged nucleus and that radiation is given off or absorbed only when an electron moves from one orbit to another.

Planck's quantum hypothesis

accurately described the radiation by assuming that electromagnetic radiation was emitted in discrete packets (or quanta).

Photons

an elementary particle, the quantum of all forms of electromagnetic radiation, including light. It is the force carrier for the electromagnetic force, even when static via virtual photons

Compton effect

an increase in wavelength of X-rays or gamma rays that occurs when they are scattered

Stationary State

an unvarying condition in a physical process.

Excited States

any quantum state of the system that has a higher energy than the ground state (that is, more energy than the absolute minimum).

Quantized

apply quantum theory to, especially form into quanta, in particular restrict the number of possible values of (a quantity) or states of (a system) so that certain variables can assume only certain discrete magnitudes.

Periodic Table

arranges the elements in horizontal rows according to increasing atomic number (number of electrons in the neutral atom.)

Fluorescense

occurs when absorbed UV photons are followed by emission of visible light due to the special arrangements of energy levels of the material.

Fine structure

precise measurements of spectral lines show tiny splitting of these lines where the energy depends very slightly on m1 and ms.

Lasers

produce a narrow beam of monchromatic coherent light (light waves in phase).