ISSN:
1434-6079
Keywords:
PACS. 31.30.Gs Hyperfine interactions and isotope effects, Jahn-Teller effect – 33.80.Be Level crossing and optical pumping – 34.30.+h Intramolecular energy transfer; intramolecular dynamics; dynamics of van der Waals molecules
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract: When a gas sample of 13CH3F is prepared with a population of isomers (ortho and para forms) far from the equilibrium given by nuclear spin statistics, it relaxes towards this equilibrium with an exponential decay rate. This phenomenon called nuclear spin conversion is mainly governed by intramolecular spin-spin and spin-rotation interactions. In the quantum relaxation model [P.L. Chapovsky, Phys. Rev. A 43, 3624 (1991)], two pairs of ortho-para levels (J = 9, K = 3; J' = 11, K' = 1) and (J = 20, K = 3; J' = 21, K' = 1) are principally responsible for the conversion. The levels of the second pair are coupled by both spin-spin and spin-rotation interactions. The application of an electric field (up to 10 kV/cm) induces a crossing of the Stark components of this pair, which is observed for the first time. A specific experimental set-up based on an electric field of alternating triangular shape is used, which allows the determination of the strength of both interactions via the measurement of the spin conversion decay rates. This work yields the first experimental value for the electronic contribution to the spin-rotation interaction in 13CH3F.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1140/epjd/e2003-00013-1
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