US EPA

8316654 

Journal Article 

Dynamics of geminate ions in the pulse radiolysis of cyclohexane and n-hexane containing aromatic solutes studied by streak camera measurements of fluorescence and absorption 

Sauer Jr., MC; Romero, C; Schmidt, KH 

1987 

1 

Radiation Physics and Chemistry
ISSN: 0969-806X 

29 

4 

261-273 

English 

The nature of geminate ion reactions in cyclohexane or n-hexane solutions irradiated with 30 ps electron pulses has been investigated by observing solute excited state fluorescence and absorption of solute ions. For the fluorescence measurements, 4-Br,4 double prime hexa(5-decyl)-p-terphenyl(BHTP) was used as the solute. The short fluorescence lifetime (0. 3 ns) of the excited singlet state of this compound (BHTP**1) facilitates the interpretation of the results. Comparison of the results with a model indicates a qualitative correspondence with the known properties of ions and electrons in the two solvents. In particular, the results support a higher mobility cation derived from the solvent in cyclohexane, compared with n-hexane. Quantitatively, however, the experimental data show a greater amount of excitation occurring within the first 20 ps (during the pulse) than is expected from the model. Results on the formation of the pyrene radical cation in cyclohexane and n-hexane solutions of pyrene also show significant differences between the two solvents, which indicate a slower formation of the pyrene cation in n-hexane.