2-mm Band and X-band electron spin resonance and electron spin-echo investigations of some carbonaceous materials

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:441417

Tsvetkov, Y D; Dzuba, S A; Gulin, V I ^[1]

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1. Institute of Chemical Kinetics and Combustion, Novosibirsk (Russian Federation)

Argonne Premium coal samples were studied by using 2-mm band and X-band continuous-wave electron spin resonance (CW ESR) and X-band electron spin-echo (ESE) spectroscopy. The line widths and g factors (Lande g factor, spectroscopic splitting factor) were determined. The correlation between {Delta}g = g{sub {parallel}} - g{sub {perpendicular}} and the carbon content in coal samples was established. Paramagnetic centers in coals could be attributed to radicals with partial redistribution of spin density from polycyclic {pi}-system to peroxide-type structures. The degree of this redistribution depends on the degree of carbonization. Phase relaxation times, T{sub 2}, for these coals were determined by using ESE spectroscopy. 5 refs., 2 figs., 3 tabs.

• OSTI ID: 441417
• Report Number(s): CONF-891206--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
40 CHEMISTRY
ANISOTROPY
CARBONACEOUS MATERIALS
CARBONIZATION
COAL
COAL RANK
DENSITY
ELECTRON SPIN RESONANCE
G VALUE
LINE WIDTHS
NUCLEAR MAGNETIC RESONANCE
RELAXATION TIME
SPECTROSCOPY
SPIN ECHO