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Negligible Nuclear Spin Relaxation Concurrent with Extensive Rotational Cooling in Jet Expansions of Methyl Halides, from Analysis of Hexapole Focusing
Author(s) -
Choi Seung E.,
Bernstein Richard B.
Publication year - 1989
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.198900060
Subject(s) - chemistry , halide , relaxation (psychology) , supersonic speed , hydrogen halide , molecule , jet (fluid) , spin (aerodynamics) , atomic physics , methyl group , hydrogen , proton , rotational temperature , molecular physics , halogen , thermodynamics , group (periodic table) , inorganic chemistry , nuclear physics , organic chemistry , physics , social psychology , alkyl , psychology
Experimental data of the UCLA group (S.R. Gandhi et al. Chem. Phys. Lett ., 1986, 132 : 6; J. Phys. Chem ., 1987, 91 : 5437) on focusing and rotational state selection of supersonic, seeded beams of methyl halide molecules via the electrostatic hexapole technique are analyzed to ascertain the extent of spin conversion (i.e., proton spin orientational relaxation) accompanying rotational cooling. Just as for the ortho‐para hydrogen system, the rate of spin conversion (here, between the two different symmetry species, A and E, of the methyl halide molecules) is found to be negligible compared to the extensive collision‐induced rotational cooling (down to rotational temperatures as low as 2 K).