Low-energy Electron Capture Research Articles

Inverse photoemission and measurements of electron affinity of solids

The method of measuring the electron affinity of solids, eχ, using radiative capture of low energy electrons is considered. In this method both the intensity of photon radiation with a specific energy, hν, and the electron current are measured as functions of the electron energy. So eχ= hν− E t, where E t is the kinetic energy threshold of the electron. The electron affinity of a solid can be determined as the maximum value of the released energy when an electron having zero kinetic energy is captured by the solid.

On low-energy nuclear electron capture

The atomic states formed in electron capture beta decay (EC) have a finite width, so that decays can take place even with energies far from the resonance energies. Here, the lineshape deviates considerably from the normally assumed Breit-Wigner form. The lineshapes far from resonance are discussed and are shown to be important in calculations of total decay rates when the Q value is low or the emitted atomic radiation is of low energy. The implications for neutrino mass searches employing electron capture decays are also discussed.

Collision-induced dissociations of negative ions. α-Dicarbonyl parent negative ions

α-Dicarbonyl compounds form stable parent negative ions by capture of low-energy electrons. The parent negative ions undergo a variety of collision induced dissociations, the most characteristic being β cleavage to a carbonyl group, i.e. see diagram in paperCyclic α-dicarbonyl parent negative ions may also eliminate molecules of carbon monoxide, for example the fragmentations M- → [M-(R + CO)]- M- →[M - (R-2CO)]- and M- → [M-2CO]- occur in a number of cases.

Low Energy Electron Capture by Multicharged Ions from Hydrogen

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Mass spectra of negative ions of nitrones and isomeric O-ethers of oximes

Interconversion of the studied nitrones and corresponding O-ethers of oximes fails to occur during the capture of low-energy electrons, and the mass spectra of the DRCE make it possible to distinguish valence isomers of this type.

Studies by the electron cyclotron resonance (ECR) technique: VIII. Interaction of low-energy electrons with the chlorine-containing molecules CCl 4, CHCl 3, CH 2Cl 2, C nH 2 n+1 Cl( n = 1 to 4). C 2H 3Cl, COCl 2, NOCl, CNCl and Cl 2

Rate constants, in some cases also activation energies and energy dependences, were measured for the capture of low-energy electrons by the molecules CCl 4, CHCl 3, CH 2Cl 2, C n H 2 n+1 Cl( n = 1 to 4), C 2H 3Cl, COCl 2, NOCl, CNCl and Cl 2 Potential energy curves were calculated for a number of negative ions. For ineffective scavengers the possibility of contributing scattering effects on the observed changes in signal intensity upon electron energy variation is indicated. In CCl 4 the observed energy dependence suggests the existence of intermediate negative ions. For Cl 2 good agreement was obtained between the calculated curves based on experimental data for electron capture and a recent self-consistent field analysis.

Cross Sections for Capture of Low Energy Electrons in H2O Vapor

Cross Sections for Capture of Low Energy Electrons in H2O Vapor

Promotion by SF6 of a Radiolytically Induced Chain Reaction for the Geometrical Isomerization of cis or trans-Butene-2 in Dilute Gaseous Mixtures

FOR several years SF6 has been used in radiolytic studies because of its high cross-section for capture of low-energy electrons and consequent effect on observable products resulting from positive-ion neutralization reactions. A reduced yield of H2 from irradiated propane has been reported1 and attributed to electron scavenging by the small proportions of SF6 present. On the other hand, SF6 does not affect the H2 yield from irradiated liquid unsaturates such as trans-butene-2 (ref. 2), indicating that ionic species may not be important with respect to H2 formation from these olefines.

Capture of Low-Energy Electrons in Chlorobenzene and Bromobenzene

Capture of Low-Energy Electrons in Chlorobenzene and Bromobenzene

Capture of Low-Energy Electrons in Chlorobenzene and Bromobenzene

Capture of Low-Energy Electrons in Chlorobenzene and Bromobenzene

Capture of Low-Energy Electrons in Chlorobenzene and Bromobenzene

Capture of Low-Energy Electrons in Chlorobenzene and Bromobenzene

Negative Ion Formation in Hydrogen Chloride by Electron Impact

The energy dependence for the formation of Cl— from HCl vapor by dissociative attachment of electrons is studied with a mass spectrometer. Within experimental error the low-energy onset for the capture process occurs at the same energy as that for the maximum capture cross section which is determined to be at 0.66 ev. The ion pair formation process, HCl+e→H++Cl—, is found to have a linear onset at 14.5 ev. The maximum yield of negative ions by this process is found to be only a few percent of that from the low-energy capture process. The energy distribution of the electron beam and the calibration of the energy scale is obtained by comparison with SF6—. It is observed that when a low-energy electron capture process is possible, spurious effects may be obtained at higher electron energies due to low-energy secondary electrons ejected from electrode surfaces by the primary beam.