title: Communications: Development and characterization of a source of rotationally cold, enriched para-H3+.
abstract: In an effort to develop a source of H(3)(+) that is almost entirely in a single quantum state (J=K=1), we have successfully generated a plasma that is enriched to approximately 83% in para-H(3)(+) at a rotational temperature of 80 K. This enrichment is a result of the nuclear spin selection rules at work in hydrogenic plasmas, which dictate that only para-H(3)(+) will form from para-H(2), and that para-H(3)(+) can be converted to ortho-H(3)(+) by subsequent reaction with H(2). This is the first experimental study in which the H(2) and H(3) (+) nuclear spin selection rules have been observed at cold temperatures. The ions were produced from a pulsed solenoid valve source, cooled by supersonic expansion, and interrogated via continuous-wave cavity ringdown spectroscopy.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA. brian.tom@usafa.edu
authors.forename: Brian A
authors.initials: BA
authors.lastname: Tom
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Mills
authors.forename: Michael B
authors.initials: MB
authors.lastname: Wiczer
authors.forename: Kyle N
authors.initials: KN
authors.lastname: Crabtree
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: McCall