Photolysis and radiolysis of cyclopentane in the liquid phase
The liquid-phase photolysis of cyclopentane has been investigated at energies below (7.6, 8.4 eV) and above (10.0, 11.6 eV) the ionization threshold (8.7 eV). The molecules excited by photon absorption and by charge recombination undergo four major dissociation processes: c-C/sub 5/H/sub 10/ ..-->.. H + c-C/sub 5/H/sub 9/ (I); c-C/sub 5/H/sub 10/ ..-->.. H/sub 2/ + c-C/sub 5/H/sub 8/ (II); c-C/sub 5/H/sub 10/ ..-->.. 1-C/sub 5/H/sub 10/ (III); and c-C/sub 5/H/sub 10/ ..-->.. C/sub 2/H/sub 4/ + C/sub 3/H/sub 6/ (IV). The quantum yields of processes I and IV increase drastically with increasing energy at the expense of process II. The ioniztion quantum yield was estimated to be 0.26 +- 0.05 and 0.4 +- 0.1 at 10.0 and 11.6 eV, respectively, based on chemical scavenging of the parent cyclopentane ions. Electron-scavenging experiments show that, in the radiolysis, neutralization (mainly geminate) of the parent ion leads to the formation of electronically excited molecules which dissociated according to processes I-IV. By comparing the relative abundances of these fragmentation channels with their quantum yields in the photolysis experiments at different energies, it is found that the average excitation energy of the cyclopentane molecules formed by charge recombination is in excess of 10 eV. Partial retention of the internal energy of the parent ions at the time of return of the geminate electron is suggested.
- Research Organization:
- National Bureau of Standards, Washington, DC
- OSTI ID:
- 6293239
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 85:16; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400500* -- Photochemistry
400600 -- Radiation Chemistry
ALKANES
CHARGED PARTICLES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
CYCLOALKANES
DECOMPOSITION
DISSOCIATION
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
FLUIDS
HYDROCARBONS
IONS
LEPTONS
LIQUIDS
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIOLYSIS
RECOMBINATION
SCAVENGING