parahelium

parahelium

[‚par·ə′hē·lē·əm]
(atomic physics)
Those states of helium in which the spins of the two electrons are antiparallel, in contrast to orthohelium. Also spelled parhelium.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Expulsion of an activated helium atom ([He.sup.*]) can lead to two conditions, depending on whether the electrons within this species are antiparallel (parahelium) or parallel (orthohelium).
Likewise, if the ground state electron is 'spin up', the excited electron must be 'spin down' to enable the transition, He* [right arrow] He + h v, again producing the identical He I lines from singlet state parahelium.