Spectroscopic notation

Spectroscopic notation

Spectroscopic notation provides various ways to specify atomic ionization states, as well as atomic and molecular orbitals.

Ionization states

Spectroscopists customarily refer to the spectrum arising from a given ionization state of a given element by the element's symbol followed by a Roman numeral. The numeral I is used for spectral lines associated with the neutral element, II for those from the first ionization state, III for those from the second ionization state, and so on. [p. 92, "Guide to the Sun", Kenneth J. H. Phillips, Cambridge, UK: Cambridge University Press, 1992. ISBN 052139788X.] For example, 'He I' denotes lines of neutral helium, and 'C IV' denotes lines arising from the third ionization state, C+++, of carbon.

Atomic and molecular orbitals

Before atomic orbitals were understood, spectroscopists discovered various distinctive series of spectral lines in atomic spectra, which they identified by letters. These letters were later associated with the azimuthal quantum number, "l". The letters, "s", "p", "d", and "f", for the first four values of "l" were chosen to be the first letters of properties of the spectral series observed in alkali metals. Letters for subsequent values of "l" were assigned in alphabetical order, omitting the letter "j": [§12-7, "An Introduction to Quantum Physics", Anthony Philip French and Edwin Floriman Taylor, CRC Press, 1979. ISBN 0748740783.] [§7.12, [http://astrowww.phys.uvic.ca/~tatum/stellatm.html "Stellar Atmospheres"] , J. B. Tatum, online book. Accessed on line September 19, 2007.] :

This notation is used to specify electron configurations and to create the term symbol for the electron states in a multi-electron atom. When writing a term symbol, the above scheme for a single electron's orbital quantum number is applied to the total orbital angular momentum associated to an electron state. [http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/hydcol.html#c3 Spectroscopic notation] , web page at http://hyperphysics.phy-astr.gsu.edu/, accessed on line September 19, 2007.]


One mnemonic phrase for remembering the sequence "S". "P". "D". "F". "G". "H". ... is "Sober Physicists Don't Find Giraffes Hiding In Kitchens Like Mine". One is expected to remember that after the "M", the letters in the sequence are alphabetical.

There are a few other mnemonic phrases for remembering the sequence, for example:
* Some Poor Damn Fool
* Smart People Don't Fail
* Silly People Drive Fast

Another mnemonic is: if you don't memorize the proper order, you will get a SPeeDy F!

Molecular Spectroscopic Notation

The spectroscopic notation of molecules uses Greek letters to represent the modulus of the orbital angular momentum along the internuclear axis.The quantum number that represents this momentum is the Λ.

Λ=0,1,2,3,...Symbols: Σ,Π,Δ,Φ

For Σ states, one denotes if there is a reflection in a plane containing the nuclei (symmetric), using the + above. The - is used to indicate that there is not.

For Homonuclear Diatomics, the index g or u denotes the existence of an inversion center.

ee also

* principal quantum number
* azimuthal quantum number
* electronic configuration
* term symbol


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Notation spectroscopique — La notation spectroscopique fournit différentes manières de spécifier les états d ionisation atomiques, ainsi que les orbitales atomiques et moléculaires. Sommaire 1 État d ionisation 2 Orbitales atomique et moléculaire 2.1 Not …   Wikipédia en Français

  • Spectroscopy — Analysis of white light by dispersing it with a prism is example of spectroscopy. Spectroscopy ( …   Wikipedia

  • Molecular symmetry — in chemistry describes the symmetry present in molecules and the classification of molecules according to their symmetry. Molecular symmetry is a fundamental concept in chemistry, as it can predict or explain many of a molecule s chemical… …   Wikipedia

  • Auger electron spectroscopy — (AES; Auger pronounced|oːʒeː in French) is a common analytical technique used specifically in the study of surfaces and, more generally, in the area of materials science. Underlying the spectroscopic technique is the Auger effect, as it has come… …   Wikipedia

  • Term symbol — In quantum mechanics, the term symbol is an abbreviated description of the angular momentum quantum numbers in a multi electron atom. It is related with the energy level of a given electron configuration. LS coupling is assumed. The ground state… …   Wikipedia

  • C parity — In physics, C parity or charge parity is a multiplicative quantum number of some particles that describes its behavior under a symmetry operation of charge conjugation (see C symmetry). Charge conjugation changes the sign of all quantic charges… …   Wikipedia

  • Quarkonium — In particle physics, quarkonium (pl. quarkonia) designates a flavorless meson whose constituents are a quark and its own antiquark. Examples of quarkonia are the J/ψ meson (an example of charmonium, cc) and the ϒ meson (bottomonium, bb). Because… …   Wikipedia

  • radioactivity — /ray dee oh ak tiv i tee/, n. Physics, Chem. the phenomenon, exhibited by and being a property of certain elements, of spontaneously emitting radiation resulting from changes in the nuclei of atoms of the element. Also called activity. [1895… …   Universalium

  • Principal quantum number — In atomic physics, the principal quantum number symbolized as n is the first of a set of quantum numbers (which includes: the principal quantum number, the azimuthal quantum number, the magnetic quantum number, and the spin quantum number) of an… …   Wikipedia

  • Molecular term symbol — In molecular physics, the molecular term symbol is a shorthand expression of the group representation and angular momenta that characterize the state of a molecule, i.e. its electronic quantum state which is an eigenstate of the electronic… …   Wikipedia