ESR and ENDOR study of the effects of x-irradiation upon single crystals of L-asparagine monohydrate from 4. 2K to room temperature

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:6921504

Coleman, J M

Single crystals of l-asparagine monohydrate and partially deuterated l-asparagine were x-irradiated at 4.2K, 77K, and room temperature by a 3 MeV Van de Graaff electron accelerator. Several free radical species were produced by the x-irradiation and were studied by X-band ESR and ENDOR from 4.2 K, to 300 K. X-irradiation at 77K produced two anion radicals, radicals I and III, with the unpaired spin at the carboxyl, and amide end of the molecule, respectively X irradiation at 77 K also produced one cation radical (II), the decarboxylation radical. The ESR spectra of radical I are the most intense. Hyperfine tensors were determined for hydrogen ENDOR lines belonging to radicals I, II, and III. In addition, ENDOR lines for one nitrogen and two deuterium lines were observed. Tensors were determined for the nitrogen and one of the deuterium nuclei. These nitrogen and deuterium couplings were needed to explain the ESR spectra of radical II. Radicals I, II, and III were also produced by x-irradiation at 4.2K. New unidentified ENDOR lines appeared after warming to 128K. Radicals I, II and III were still observed at this temperature, but the ESR spectra have changed somewhat. After warming to 150K, radical I's ESR spectrum was not observed. Upon warming to 210 K, radical II began decay by hydrogen abstraction to form radical IV which was identified in an earlier room temperature study.

• Research Organization: Florida State Univ., Tallahassee (USA)
• OSTI ID: 6921504
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
AMIDES
AMINO ACIDS
ASPARAGINE
BEAMS
CARBOXYLIC ACIDS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
CRYSTALS
DATA
DECOMPOSITION
DEUTERIUM COMPOUNDS
ELECTROMAGNETIC RADIATION
ELECTRON BEAMS
ELECTRON SPIN RESONANCE
ENDOR
ENERGY RANGE
EXPERIMENTAL DATA
HYDROGEN COMPOUNDS
INFORMATION
IONIZING RADIATIONS
LEPTON BEAMS
LOW TEMPERATURE
MAGNETIC RESONANCE
MEDIUM TEMPERATURE
MEV RANGE
MEV RANGE 01-10
MONOCRYSTALS
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PARTICLE BEAMS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADIOLYSIS
RESONANCE
ULTRALOW TEMPERATURE
X RADIATION