Isotopic effects on the decay kinetics of the 385-nm luminescence from electron-irradiated ice. [Electron irradiation]

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100172a039· OSTI ID:7265692

Vernon, C F; Matich, A J; Quickenden, T I ^[1]; Sangster, D F ^[2]

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1. Univ. of Western Australia, Nedlands (Australia)
2. Univ. of Sydney (Australia)

The effect of isotopic substitution of D for H on the decay kinetics of the 385-nm luminescence peak from electron-irradiated ice has been determined at 78 K. Each luminescence decay was analyzed into a long-lived, first-order component (t{sub 1/2}=690{plus minus}34 ns for H{sub 2}O and 1820{plus minus}96 ns for D{sub 2}O) and a superimposed short-lived decay which obeyed second-order kinetics. The ratio of the first-order rate constants, k(H{sub 2}O)/k(D{sub 2}O), was 2.7{plus minus}0.3, which agrees with the value of 2.7 for the ratio of the mobilities of protons and deuterons in their respective ices. This suggests that proton migration is the rate-determining step in the luminescence mechanism. The suggested mechanism involves migration of H{sup +} to OH{sup {minus}} formed from trapped OH and the subsequent formation of excited water molecules in the associative C{sup 1}B{sub 1} state. The water molecules then decay to the dissociative A{sup 1}B{sub 1} state, emitting broad-band excimer luminescence peaking at 385 nm.

• OSTI ID: 7265692
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:19; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400202* -- Isotope Effects
Isotope Exchange
& Isotope Separation
400600 -- Radiation Chemistry
ANIONS
BARYONS
BEAMS
CHARGED PARTICLES
DATA
DEUTERONS
ELECTROMAGNETIC RADIATION
ELECTRON BEAMS
ELEMENTARY PARTICLES
ENERGY LEVELS
EXCITED STATES
EXPERIMENTAL DATA
FERMIONS
HADRONS
HYDROGEN COMPOUNDS
HYDROXIDES
ICE
INFORMATION
ION MOBILITY
IONS
ISOTOPE EFFECTS
KINETICS
LEPTON BEAMS
LUMINESCENCE
MOBILITY
NUCLEONS
NUMERICAL DATA
OXYGEN COMPOUNDS
PARTICLE BEAMS
PARTICLE MOBILITY
PROTONS
RADIATIONS
VISIBLE RADIATION