Autoionization in Photoelectron Emission by Solutions: Anthracene Anion Radicals.
NEW YORK UNIV N Y DEPT OF CHEMISTRY
Pagination or Media Count:
Photoelectron emission PEE spectra up to 5 eV of anthracene anion radicals A- and A2- in tetrahydrofuran THF and hexamethyl phosphoric triamide HMPA exhibit three bands with maxima at photon energies about 3.35, 3.8 and 4.8 eV nearly coinciding with the energies at the maxima of absorption bands. PEE is interpreted as arising primarily from autoionization of excited states of the 3.35, 3.8 and 4.8 eV bands into the continuum located above the 1.7 eV absorption band. Direct transition to the continuum appears minor except possibly at the foot of the first PEE band. Quantum yields for A- in THF are lower than in HMPA because stronger ion pairing in THF favors geminate recombination of parents with emitted quasi-free electrons. Anthracene in THF or HMPA and the cation A in dichloromethane and fluorosulfonic acid do not exhibit any PEE because the continuum is too high to allow autoionization or direct bound-continuum transitions. These are the first reported examples of autoionization in solutions. Author
- Atomic and Molecular Physics and Spectroscopy