H/D isotope effects in water radiolysis. 3. Atomic hydrogen in acidic H sub 2 O/D sub 2 O mixtures. [Accelerated electrons]

Journal Article · Thu Nov 14 00:00:00 EST 1991 · Journal of Physical Chemistry; (United States)

OSTI ID:7163337

Han, Ping; Bartels, D M ^[1]

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1. Argonne National Lab., IL (United States)

The authors present measurements of the EPR spectra of H and D atoms immediately (30-50 ns) following pulse radiolysis of acidic H{sub 2}O/D{sub 2}O mixtures with 3-MeV electrons. The spectra exhibit a low-field emission/high-field absorption (E/A) polarization pattern of chemically induced dynamic electron polarization (CIDEP), which is characteristic of random (uncorrelated spin) recombination reactions of free radicals in the radiolysis spurs. As in previous works, the CIDEP amplitudes are analyzed to deduce the isotope effect {alpha} = (H/D){sub product}/(H/D){sub water} which characterizes the formation of the H and D atoms. The relative H and D signal intensities can be accounted for in terms of two strong isotope effects demonstrated in previous work: (a) reaction of hydrated electrons with hydronium ions to give H (or D) and (b) the dissociation of the electronically excited HDO* molecule to give preferentially H. It is estimated that the direct dissociation channel accounts for G{congruent} 0.3 of the atomic hydrogen yield in radiolysis of both acidic and alkaline water.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 7163337
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 95:23; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
HEAVY WATER
RADIOLYSIS
WATER
DISSOCIATION
ELECTRON BEAMS
EXCITED STATES
HYDRATION
INORGANIC ACIDS
ISOTOPE EFFECTS
RADICALS
SOLVATED ELECTRONS
BEAMS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
DECOMPOSITION
ELECTRONS
ELEMENTARY PARTICLES
ENERGY LEVELS
FERMIONS
HYDROGEN COMPOUNDS
LEPTON BEAMS
LEPTONS
OXYGEN COMPOUNDS
PARTICLE BEAMS
RADIATION EFFECTS
SOLVATION
400202* - Isotope Effects
Isotope Exchange
& Isotope Separation
400600 - Radiation Chemistry