Pulse radiolysis study on electrons trapped in semiclathrates and non-clathrate hydrates
Trapping of electrons in specific water molecule vacancies, observed previously in crystalline aqueous clathrates, has also been found in semiclathrates (e.g., tetramethylammonium hydroxide pentahydrate), in clathrates showing hydrogen bonds between host and guest molecules (e.g., piperazine clathrate), and also in inorganic hydrates (e.g., sodium carbonate decahydrate). The lifetime of the electron is sometimes longer than in the case of true clathrates; e.g., t/sub 1/2/ = 3.5 ms (first-order decay in piperazine clathrate). The existence of comparatively long-lived electrons at room temperature may be considered a general phenomenon. The condition for its occurrence is the presence of OH/sup -/ or F/sup -/ anion, which can substitute for H/sub 2/O in the aqueous part of the compound and when displaced leaves an electron trap. In other ionic and nonionic compounds, the condition for the trapping of long-lived electrons is protonation of the principal compound, thereby leaving the solution or melt alkaline during the crystallization of the hydrate. Interpretation in terms of preexistent traps invokes the crystal imperfections chemistry, which in the case of hydrates has not yet been noticed. It has been assumed that electrons occupy the vacancies temporarily revealing their presence. In some clathrates and other hydrates, the long-lived electron traps do not occur; instead, the electron shows a similar spectrum (620 nm maximum), decaying by 2-3 orders of magnitude faster than in long-lived traps. It is assumed that this is a case of electron digging its own hole, although an alternative explanation may be through trapping in other kinds of crystal imperfections in the aqueous moiety of the hydrate.
- Research Organization:
- Univ. of Notre Dame, IN
- OSTI ID:
- 6770924
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 91:4
- Country of Publication:
- United States
- Language:
- English
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ALUMINIUM COMPOUNDS
RADIOLYSIS
AMMONIUM COMPOUNDS
CARBONATES
CLATHRATES
FLUORIDES
HYDRATES
HYDROXIDES
PIPERAZINES
POTASSIUM COMPOUNDS
SILICATES
SODIUM COMPOUNDS
SULFATES
UROTROPIN
ELECTRONS
EXPERIMENTAL DATA
MATRIX ISOLATION
MEDIUM TEMPERATURE
PULSE TECHNIQUES
ALKALI METAL COMPOUNDS
AMINES
AZINES
CARBON COMPOUNDS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DATA
DECOMPOSITION
ELEMENTARY PARTICLES
FERMIONS
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
INFORMATION
LEPTONS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PYRAZINES
RADIATION CHEMISTRY
RADIATION EFFECTS
SILICON COMPOUNDS
SULFUR COMPOUNDS
400600* - Radiation Chemistry