Spectra, yields, and photolability of cations, carbanions, radicals, and scavenger anions in. gamma. -irradiated alkane glasses
The overlapping spectra of the cations, carbanions, and radicals responsible for the broad observed spectrum from 200 to 800 nm in ..gamma..-irradiated alkane glasses at cryogenic temperatures have been resolved in 3-methylpentane (3MP) and 2-methylpentane (2MP). Extinction coefficients have been assigned to these species and to the scavenger anions SF/sub 6//sup -/, Cl/sub 2//sup -/, and Br/sub 2//sup -/ formed in the glasses. The lambda/sub max/ values in 3MP, and the extinction coefficients are as follows: 3MP/sup +/, 490 nm, 153 M/sup -1/ cm/sup -1/; R., 218 nm, 1675 M/sup -1/ cm/sup -1/; R:/sup -/, 240 nm, 6300 M/sup -1/ cm/sup -1/; SF/sub 6//sup -/, epsilon/sup 350/ = 573 M/sup -1/ cm/sup -1/; Cl/sub 2//sup -/, 350 nm, 3257 M/sup -1/ cm/sup -1/; Br/sub 2//sup -/, 365 nm, 4238 M/sup -1/ cm/sup -1/. In 3MP which has received a 2.8 x 10/sup 19/ eV g/sup -1/ ..gamma.. dose at 68 K, G(R:/sup -/) is approx. 0.3. Nearly all of the e/sup -/ produced by photoejection from the R:/sup -/ are trapped by the matrix rather than reacting with cations. When the e/sub t//sup -/ are mobilized by IR light, approx. 12% react with R. to form R:/sup -/ and 88% neutralize cations. The ratio of radicals formed by the neutralization process to electrons neutralized is 0.27. The trapped cations can be removed by exposure to light in their absorption band. In 3MP and 2MP containing both the electron scavenger SF/sub 6/ and the positive charge scavenger 2MP-1, G(cations) = G(anions) = 5.4 +- 0.5. 8 figures, 3 tables.
- Research Organization:
- Univ. of Wisconsin, Madison
- DOE Contract Number:
- EY-76-S-02-1715
- OSTI ID:
- 5068044
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 84:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALKANES
RADIOLYSIS
ANIONS
G VALUE
CATIONS
RADICALS
ABSORPTION SPECTRA
BROMIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHLORIDES
EXPERIMENTAL DATA
GAMMA RADIATION
INFRARED SPECTRA
LOW TEMPERATURE
SCAVENGING
SULFUR FLUORIDES
TEMPERATURE DEPENDENCE
BROMINE COMPOUNDS
CHARGED PARTICLES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
CHLORINE COMPOUNDS
DATA
DECOMPOSITION
ELECTROMAGNETIC RADIATION
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HYDROCARBONS
INFORMATION
IONIZING RADIATIONS
IONS
KINETICS
NUMERICAL DATA
ORGANIC COMPOUNDS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
REACTION KINETICS
SPECTRA
SULFUR COMPOUNDS
YIELDS
400600* - Radiation Chemistry