The total electron attachment rate constant ka(〈e〉) for CClF3 and C2F6 has been meausured using an electron swarm technique in the mean electron energy range 0.41 to 4.81 eV and over the range of temperature T from 300 to 750 K. At each value of T the total electron attachment cross section σa(e) was determined from the measured ka(〈e〉) using the swarm unfolding technique and was compared with the results of a mass spectrometric study. The σa(e) for C2F6 shows a single peak (due to F− and CF3−) which shifts from 3.9 eV at 300 K to ∼3.3 eV at 750 K. (The onset shifts correspondingly from 2.3 to 1.5 eV.) For CClF3 the σa(e) shows two peaks: at ∼1.5 eV (due to Cl−) and at ∼4.7 eV (due to Cl−, F−, CClF2−, and ClF−). The peak at ∼1.5 eV is especially sensitive to changes in T. The peak value of σa(e) increased by a factor of ∼3, and the energy position of the peak and onset shifted to progressively lower energies when T increased from 300 to 700 K. The analysis of these results led us to conclude that the chan...

Effect of temperature on the dissociative electron attachment to CClF3 and C2F6 a)

We review briefly but comprehensively the theoretical, semiempirical and experimental methods employed to determine electron affinities (EAs) of atoms, molecules and radicals, and summarize the EA data obtained by these methods. The detailed processes underlying the principles of the experimental methods are discussed very briefly. It is, nonetheless, instructive to recapitulate the definition of EA and those of the related quantities, namely, the vertical detachment energy, VDE, and the vertical attachment energy, VAE. The EA of an atom is defined as the difference in total energy between the ground state of the neutral atom (plus the electron at rest at infinity) and its negative ion. The EA of a molecule is defined as the difference in energy between the neutral molecule plus an electron at rest at infinity and the molecular negative ion when both, the neutral molecules and the negative ion, are in their ground electronic, vibrational and rotational states. The VDE is defined as the minimum energy required to eject the electron from the negative ion (in its ground electronic and nuclear state) without changing the internuclear separation; since the vertical transition may leave the neutral molecule in an excited vibrational/rotational state, the VDE, although the same as more » the EA for atoms is, in general, different (larger than), from the EA for molecules. Similarly, the VAE is defined as the difference in energy between the neutral molecule in its ground electronic, vibrational and rotational states plus an electron at rest at infinity and the molecular negative ion formed by addition of an electron to the neutral molecule without allowing a change in the intermolecular separation of the constituent nuclei; it is a quantity appropriate to those cases where the lowest negative ion state lies above the ground states of the neutral species and is less or equal to EA. « less

Electron Affinities of Atoms, Molecules, and Radicals

Survey of main group compounds (HBr) at the Gaussian-4 level of theory: Adiabatic ionization energies and enthalpies of formation

Electron affinities of atoms, molecules and radicals

When a Ne:NF3 sample is codeposited at approximately 5 K with a beam of pure neon that has been passed through a microwave discharge, the infrared spectrum of the resulting deposit includes prominent absorptions of NF2 and a structured absorption assigned to NF. In addition, two groups of absorptions contributed by previously unassigned products can be distinguished, based on their behavior on subsequent filtered mercury‐arc irradiation of the deposit. Three absorptions which disappear readily on near‐ultraviolet irradiation are assigned to NF−2. The remaining absorptions are contributed by NF+3 and probably also by NF+2. Vibrational assignments for these absorptions are proposed, and processes which occur on mercury‐arc irradiation of the deposit are considered.

Matrix isolation study of the interaction of excited neon atoms with NF3. Infrared spectra of NF+3, NF+2, and NF−2

1

Study has been made of the ionization of ClF3, ClF2, and ClF molecules with the formation of positive and negative ions




2

The energy of atomization of ClF2, the heat of formation of ClF2, and the F2Cl-F and FCl-F bond energies have been calculated




3

The lower limit of the electron affinity of the ClF molecule has been determined

A study of the electron-impact ionization of chlorine trifluoride and its decomposition products by mass spectrometry

1.

The authors have investigated electron shock ionization of the NF3 molecule with formation of positive and negative ions. They have measured the appearance potential and the initial kinetic energies of the ions.




2.

They have calcualted the splitting energies of the bonds D0(FN-F) and D0(N-F) and the lower limit of the electron affinity of the NF2 radical.

A mass-spectrometric investigation of nitrogen trifluoride by the electron shock method

Electron-impact methods have been used to study positive (NF+, NF2+, N2F2+) and negative (F−, F2−, N2F−, NF2−) ion formation in the mass spectra of tetrafluorohydrazine and its decomposition products.

Mass-spectrometric study of tetrafluorohydrazine and the products resulting from its breakdown under electron impact

1.

Using electron impact the authors investigate ionization of the ClF5 molecule with formation of positive and negative ions. They measure the appearance potentials and excess kinetic energies of the ions.




2.

They calculate the lower values of the electron affinity of ClF2 and ClF3 molecules and the upper limit of the ionization potential of the ClF4, radical.

L. N. Gorokhov

Papers

A study of the electron-impact ionization of chlorine trifluoride and its decomposition products by mass spectrometry

A mass-spectrometric investigation of nitrogen trifluoride by the electron shock method

Mass-spectrometric study of tetrafluorohydrazine and the products resulting from its breakdown under electron impact

A mass-spectrometric investigation of ionization of chlorine pentafluoride by electron impact