Electronic spectra of the free allyl radical and some of its simple derivatives

Abstract

Electronic spectra in the 2100-2500 8, region, were reported for the allyl radical, the P-methallyl radical, the cc-methallyl radical, the p-ethallyl radical and the cyclopentenyl radical. The vibrational structures of the allyl and P substituted radicals indicate that in the main regions of absorption, the a(C-13) stretching frequency is excited. A single band progression observed in flashed allyl cyanide, was tentatively assigned to a free radical derived from pyrrole.

Vibronic structure of the 3s Rydberg state of the 2-methylallyl radical

“…The 2-methylallyl radical has been studied using a range of spectroscopic methods including electron spin resonance [1], photoelectron [2], absorption [3,4], resonance Raman [5,6], and photofragment action spectroscopy [7]. The 2-methylallyl radical was first produced in the gas phase by Callear and Lee [3] by pyrolysis of various radical precursors. The authors reported a structured absorption in the ultraviolet (UV) in the range between 220 and 260 nm.…”

The nonradiative decay of the allyl radical excited B 2A1 state studied by picosecond time-resolved photoelectron spectroscopy

“…Its photochemistry upon UV excitation is thus of considerable relevance for tropospheric chemistry and combustion. The UV band system, starting at 250 nm and observed first in absorption, 1 was studied by resonant multiphoton ionization ͑MPI͒, 2-5 allowing the identification of a large number of vibronic bands and their assignment to the electronic B, C, and D states, which are strongly coupled with each other. Resonance Raman spectra from these states were also recorded, 6 but no fluorescence has been observed, despite the large oscillator strength calculated for the C←X transition, 7 indicating short lifetimes.…”

Time-resolved photoelectron spectroscopy of the allyl radical: The lifetimes of the ultraviolet bands

“…5 The location of the electronic A state was derived from an unassigned, but well resolved absorption spectrum. 6 The UV band system starting at 250 nm was studied in detail by absorption spectroscopy, 7 multiphoton ionization, [8][9][10][11][12] and resonance Raman spectroscopy. 4,13,14 Excited state geometries were derived from partially rotationally resolved MPI spectra.…”