Experimental determination of the oscillator strength of the B(²B₁)—X(²A₂) transition of the free allyl radical

Abstract

The integrated absorption of the P1-X transition of the methyl radical (2160 A) and the B-X transition of the allyl radical (2100-2400 A) were compared, in the flash photolysis of butene-1.From thef-value of the CH3 band, the oscillator strength of the allyl transition was recorded as 0.140 (rf0.028). The rate coefficient for recombination of allyl radicals was in the range 8.5(f3)x loi2 cm3 mol-l s-l.

Reactions of trifluoromethyl radicals with iodine and nitric oxide

“…Both these facts provide some support to our assuniption that reaction 2 is second order. Furthermore, our value obtained for k3 (second order) is of the same order of magnitude as the recently obtained (16,17) values for kI2 (second order). Our results also indicate that reaction 3 has an activation energy fairly close to zero in the range 68-189 "C which is consistent with the fact that k3 is siniilar in magnitude to Z3.…”

“…These results are surprising since one would not normally expect such differences in behaviour between CF3 and CH3 radicals especially since Christie estimates that for CH3 k14 = 3.0 X lo9 I 11101-I s-I whereas for CF3 k14 = 7.5 X lo8 1 iiiol-I s-l. However, using the latest reported values of k13 for CH3 (16,17) we have kI3/k14 = 1-3.3.…”

The rate of dissociation of allyl iodide in shock waves

“…Later we attempted to estimate the most probable value of k4, following considerations presented by Benson and O'Neal [14], and obtained loglo k4 = 12.0. At about the same time, we became aware of experimental measurements of k4 by Golden et al [18] and by Vandenberg and Callear [19], both of which fall in the vicinity of loglo k4 = 12.8. Therefore, a supplementary set of profiles was computed in which k4 was varied over the full range of values in order to assess its effect (particularly upon temperature corrections).…”

Single-photon and resonance-enhanced multiphoton threshold ionization of the allyl radical

“…The electronic spectrum of allyl has been studied extensively and the structural and dynamic properties of many vibronically excited states of allyl have been characterized by optical spectroscopy. [1][2][3][4][5][6] The ground electronic state of allyl has also been investigated by electron spin resonance ͑ESR͒ spectroscopy. 7,8 From these ESR studies and theoretical investigations, 9 the spin density in the ground state radical was determined to be mainly localized at the terminal carbon atoms.…”