Yield of excited singlet and triplet states in the pulse radiolysis of toluene

Abstract

The 100 eV yield of the excited singlet state of toluene following a pulse of 10 MeV electrons is found to be 1.35, and the rate constant for its reaction with naphthalene to give the excited naphthalene singlet is 5 . 4 ~ 1O'O M-l s-l. The corresponding yield of the triplet state of toluene is 2.8 and assuming it reacts with naphthalene at a normal diffusion controlled rate, its half life is calculated to be 17 ns. Recent pulse radiolysis workon excited states in solutions of aromatics has reconciled previously conflicting estimates of the yields of excited states of benzene produced on the absorption of ionising radiation. We now present a parallel study on toluene for which the corresponding yields are in some doubt.3* EXPERIMENTAL MATERIALS Analytical reagent benzene was recrystallised three times before use. Scintillation grade toluene was fractionated from lithium aluminium hydride and stored over sodium wire in an argon atmosphere. Purity was checked by vapour phase chromatography using a flame ionization detector. Naphthalene was scintillation grade. All solutions were deoxygenated by prolonged bubbling with pure argon.

Controlling and Fine-Tuning Charge-Transfer Emission in 2,6-Dicyanoaniline Multichromophores Prepared through Domino Reactions: Entry to a Potentially New Class of OLEDs

“…To corroborate the assignment of the third species as the T 1 state, radiation chemical measurements, namely, pulse radiolysis experiments, of 1 and 2 in nitrogen-saturated toluene were conducted. Under these conditions, the radiolysis leads to the formation of 3* toluene, which undergoes a Dexter energy transfer to form 3* 1 and 3* 2 . As a result, the obtained spectra by pulse radiolysis match well the spectral species of the third state from the SVD analysis of the laser photolysis transient absorption data (see Figures b and S1 in the SI), confirming its assignment as the T 1 state.…”

“…Under these conditions, the radiolysis leads to the formation of 3 *toluene, which undergoes a Dexter energy transfer to form 3 *1 and 3 *2. 47 As a result, the obtained spectra by pulse radiolysis match well the spectral species of the third state from the SVD analysis of the laser photolysis transient absorption data (see Figures 7b and S1 in the SI), confirming its assignment as the T 1 state.…”

Radiolysis of ferric hexafluoroacetylacetonate–toluene solutions

“…Fe(HFA)3, however, does not react with +CH2 but does scavenge these unknown radical radiolysis products. If [2] is the only source of +CH2CH2+ then the yield of primary and secondary 4 6~~ may be as large as 0.6 and the yield of the unknown radicals, which are trapped by Fe(HFA)3, is -0. 4. …”

“…[Traduit par le journal] Isatroductiosp In the radiolysis of liquid toluene very rapid isra recon-ibinations (1) result in the formation of excited siizglei and triplet states (+CH3*) with G(+CH3*) -4-5 molecu!es/100 eV (2,3). A small percentage of these states are converted to radicals as the yield of sadica!~ captured by the 'Present address: Analytical Chemistry Branch, Whiteshell Nuclear Research Establishment, Pinawa, Manitoba.…”

Low-Dose High-Resolution TOF-PET Using Ionization-activated Multi-State Low-Z Detector Media

“…The number of activated molecules is proportional to the deposited ionization energy, with a conversion factor that can be more than 10 4 molecules per MeV [61]. By way of illustration, in toluene there are initially 1.35 × 10 4 singlet excitations per MeV from 10 MeV electrons [64]. To achieve a 1% energy resolution at 511 KeV requires 20,000 activated Switchillator fluorophore molecules per MeV.…”