Examination of the exchange interaction through micelle size. 2. Isotope separation efficiency as an experimental probe

Journal Article · Wed Mar 23 04:00:00 EST 1994 · Journal of the American Chemical Society; (United States)

DOI:https://doi.org/10.1021/ja00085a007· OSTI ID:7267350

Tarasov, V F; Buchachenko, A L ^[1]; Ghatlia, N D; Turro, N J ^[2]; Avdievich, N I ^[3]; Shkrob, I A ^[4]

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1. Inst. of Chemical Physics, Moscow (Russian Federation)
2. Columbia Univ., New York, NY (United States)
3. International Tomography Center, Novosibirsk (Russian Federation)
4. Argonne National Lab., IL (United States)

The geminate reaction probabilities (for recombination and disproportionation) of benzoyl/sec-phenethyl radical pairs, generated by the photolysis of [alpha]-methyldeoxybenzoin, for both unlabeled ([sup 13]C in natural abundance at the carbonyl position) and labeled ketones ([sup 13]C in the carbonyl position) were measured in different sized alkyl sulfate micelles (sodium octyl sulfate (C[sub g]) through sodium dodecyl sulfate (C[sub 12])) in zero and high magnetic fields (B = 2400 G). Although the probability of geminate recombination (P[sub t]) diminishes for the unlabeled pair, from 0.549 to 0.436 and for the labeled pair from 0.585 to 0.504 at zero magnetic field with decreasing micelle size (C[sub 12] to C[sub 8]), the efficiency of isotope separation ([alpha]) is found to increase at zero magnetic field from 1.144 to 1.236 with decreasing micelle size. Theoretical considerations of these experimental results show that the rate of geminate reaction of the unlabeled radical pairs in small micelles is sensitive to the electron spin exchange interaction; intersystem crossing is influenced by fast forced reencounters. These effects are not as important for the labeled radical pairs (which possess a strong [sup 13]C hyperfine interaction). 40 refs., 6 figs., 3 tabs.

• OSTI ID: 7267350
• Journal Information: Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 116:6; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
AROMATICS
ARYL RADICALS
BENZOYL RADICALS
CARBON 13
CARBON ISOTOPES
CHEMICAL REACTIONS
CHROMATOGRAPHY
DATA
DECOMPOSITION
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
GAS CHROMATOGRAPHY
INFORMATION
ISOTOPES
KETONES
LIGHT NUCLEI
MAGNETIC FIELDS
MASS SPECTROSCOPY
MATHEMATICAL MODELS
MICELLAR SYSTEMS
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
PHENETHYL RADICALS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PROBABILITY
RADICALS
RECOMBINATION
SEPARATION PROCESSES
SPECTROSCOPY
STABLE ISOTOPES
SURFACTANTS
THEORETICAL DATA