Transient resonance coherent anti-Stokes Raman scattering spectra of ion radicals of all-trans-1,4-diphenyl-1,3-butadiene

Picosecond CARS and Transient Absorption Studies of 1,4-Diphenylbutadiene and trans-Stilbene: A Study of Photoinduced Formation of a Radical Cation

“…After a rise time well fitted by a 20 ( 5 ps exponential growth, no further shift was observed. This is in good agreement with the results of Dudev et al 2 who measured CARS spectra of the DPB cation radical and observed a shift of 23 cm -1 between DPB S 1 and DPB •+ bands located respectively at 1575 and 1598 cm -1 .…”

“…Moreover, they estimated the lifetime of the cation to be about 500 ns. 2 According to those results and the similarities to our observations, it is quite natural to attribute these new bands to cation formation. Yet, concerning the exact mechanism of formation of the radical cation, these partial results could not lead to precise interpretations.…”

“…Among the possible processes that can occur after excitation, direct photoionization and production of ion radicals has been observed at nanosecond time resolution. 2 Although the excitation wavelength was well below the photoionization threshold, it was unambiguously shown that in a polar solvent, direct formation of radical ions occurs. It was demonstrated that this process involves a lowering, by solvent interaction, of the ionization threshold, which allows direct photoionization.…”

Electron delocalization in mixed-valence butadienediyl-bridged diruthenium complexes

“…In this respect we note that the radical anion and cation of all-trans 1,4-diphenylbutadiene also have structured absorption at 560 or 546 nm [69]. Irradiation into this band results, inter alia, in the resonance enhancement of Raman bands at 1215 and 1176 or 1250 and 1298 cm -I, respectively [70] .…”

Dynamics of electron ejection on photoionization of trans-stilbene and biphenyl in acetonitrile as observed with femtosecond time-resolved near-IR absorption spectroscopy

“…Photoionization in solution has been drawing attention as a fundamental but complex process in chemical reactions, as temporal behaviors of a solute, an ejected electron and surrounding solvent molecules need to be elucidated for explaining its mechanism. [1][2][3][4][5][6][7] When an electrically neutral molecule is photoexcited to a highly excited state above the ionization potential, an electron can be ejected from the molecule, leaving the parent molecule as the radical cation. The highly excited state can be an excited singlet state 8,9 and a Rydberg state.…”