Deuterium isotope and molecular structure effects on charge trapping and scavenging in. gamma. -irradiated glassy hydrocarbons

Journal Article · Sun Oct 01 04:00:00 EDT 1978 · J. Chem. Phys.; (United States)

OSTI ID:6644950

Wang, H Y; Willard, J E

An investigation of the cause of the higher (by a factor of approx.1.5) yields of trapped electrons (G (e/sup -//sub t/)) produced by the ..gamma.. irradiation of 3-methylpentane-d/sub 14/ (3MP-d/sub 14/), methylcyclohexane-d/sub 14/ (MCHx-d/sub 14/), and 3-methylheptane-d/sub 18/ (3MHp-d/sub 18/) glasses at 77 K as compared to 3MP-h/sub 14/, MCHx-h/sub 14/, and 3MHp-h/sub 18/ has provided new evidence and insight on such isotope effects and on the effects of molecular structure on G (e/sup -//sub t/). The absolute reduction in G (e/sup -//sub t/) by a given concentration of the electron scavengers SF/sub 6/, CH/sub 3/I, and biphenyl (phi/sub 2/) is always greater in the deuterated than in the protiated form of 3MP or MCHx. G (phi/sup -//sub 2/) from the scavenging of e/sup -/ by phi/sub 2/ is higher in 3MP-d/sub 14/ than 3MP-h/sub 14/, in MCHx-d/sub 14/ than in MCHx-h/sub 14/ and in either form of 3MP than MCHx. The fractional decay rate of e/sup -//sub t/ is slower in deuterated than protiated matrices both at the glass transition temperature and below, and is faster than the fractional decay rate of trapped radicals. The decay rates are reduced by positive charge scavengers. G (TMPD/sup +/) from the scavenging of positive charge by tetramethylparaphenylenediamine (TMPD) is the same, independent of deuteration, in 3MP-d/sub 14/ and in 3MP-h/sub 14/ glasses and varies with molecular structure. The positive charge scavengers 2-methyl-1-pentene (2MP-1), triethylamine (TEA), and propene (C/sub 3/H/sub 6/ and C/sub 3/D/sub 6/) each cause an equal or greater absolute increase in G (e/sup -//sub t/) in perdeuterated than in the corresponding protiated matrices. They give different profiles of enhancement vs concentration in different alkanes. C/sub 3/H/sub 6/ and C/sub 3/D/sub 6/ produce different G (3/sup -//sub t/) enhancement profiles when compared in the same matrix. The optical spectra of e/sup -//sub t/ in deuterated and protiated alkanes and alkanes of different molecular structure are similar.

• Research Organization: Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706
• OSTI ID: 6644950
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 69:7; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400302 -- Organic Chemistry-- Isotope Effects-- (-1987)
400600* -- Radiation Chemistry
ALKANES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
CYCLOALKANES
DECOMPOSITION
DEUTERIUM
ELECTROMAGNETIC RADIATION
GAMMA RADIATION
HYDROCARBONS
HYDROGEN ISOTOPES
IONIZING RADIATIONS
ISOTOPE EFFECTS
ISOTOPES
LIGHT NUCLEI
MOLECULAR STRUCTURE
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADIOLYSIS
SCAVENGING
STABLE ISOTOPES