The Ionization and Dissociation of Complex Molecules by Electron Impact

Craggs, J D; McDowell, C. A.

doi:10.1088/0034-4885/18/1/309

Cited by 19 publications

(6 citation statements)

References 104 publications

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“…In a recent experiment with CCI4, a new 60 0 sector field instrument was used, and, probably because of improved means of focusing , some details were observed that were unmeasurable with the 180 0 instrument. In an experiment with C2F6 a tungsten filament coated 1 Figures in brackets indicate t he literature references at the end of this paper.…”

Section: Methodsmentioning

confidence: 99%

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A survey of negative ions in mass spectra of polyatomic molecules

Reese¹,

Dibeler²,

Mohler³

1956

J. RES. NATL. BUR. STAN.

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A s urvey was made of negative-ion production in 27 different molecules covering a wide variety of chemical compounds. In nine compounds no ions were found. For the other cOlr>pounds rough measurements of the appearance potentials and relative abundance of the ions are reported . About 60 different ionization processes are observed in 18 compounds. Formation of ion s by dissoc iative resonance attachment is t he most common process, but there are several cases of ion pair formation and of attachment without dissociation. Perchlorylfluoride gives by far t he greatest abundance and variety of ions.

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Section: Methodsmentioning

confidence: 99%

“…Experimental data on mass spectra of negative ions [1,2,3,4]] are fragmentary and incomplete as compared with the extensive volume of research on positive ions. There are three different mechanisms by which negative ions can be formed by electron collision.…”

Section: Introductionmentioning

confidence: 99%

A survey of negative ions in mass spectra of polyatomic molecules

Reese¹,

Dibeler²,

Mohler³

1956

J. RES. NATL. BUR. STAN.

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“…According to Laidler (1954), Craggs and McDowell (1955), and others, the dominant attachment process for energies up to about lO e V is the following resonance capture process:…”

Section: R Introductionmentioning

confidence: 99%

The Diffusion and Attachment of Electrons in Water Vapour

Crompton¹,

Rees²,

Jory³

1965

Aust. J. Phys.

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SummaryThe energy ratio and attachment coefficient for electrons in water vapour have been determined in the range 20 < Elp < 60 V cm-l torr-l. The results for the attachment coefficient are in general agreement with other recent determina· tions, but those for the energy ratio differ significantly from the results of Bailey and Duncanson. The use of these new data, in conjunction with values of the drift velocity determined by Pack, Voshall, and Phelps, is shown to remove the serious discrepancy which previously existed between the results of single-collision and swarm experiments. r. INTRODUCTIONWhen electrons having energies of the order of 5 e V pass through water vapour at a pressure of a few torr, an appreciable fraction of the electrons form negative ions by electron attachment. According to Laidler (1954), Craggs and McDowell (1955), and others, the dominant attachment process for energies up to about lO e V is the following resonance capture process:(1)Laidler states that the water molecule is first raised to a repulsive 2Al or 2A2 state of H 2 0-which at once dissociates into H -(IS) and OH(27T). The appearance potential is of the order of 5·5 e V, and the cross section is a maximum for electrons having energies of about 6·5 eV.The curve showing the variation with electron energy of the rate of production of H -ions from H 2 0 shows a second, smaller peak which has a maximum value at an energy of about 8·5 eV (Mann, Hustrulid, and Tate 1940; Buchel'nikova 1959). For electrons of energy greater than about 7·5 eV, 0-ions may also be produced, the reaction being (2) It is widely believed (see, for example, Cottin 1959) that the H-ions formed as above are rapidly converted to negative hydroxyl ions by the following process:At gas pressures of the order of 1 torr, Branscomb and Smith (1955) and Muschlitz and Bailey (1956) observed that the OH-ions so formed were considerably more abundant than either H -or 0-ions.

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“…report a contribution to the Cl¯ yield at around 13 eV in an early study and attributed this contribution to DD. Similarly Craggs and McDowell[122] Cl¯ formation from CCl4 with an AE of 12.2 eV and a minimum kinetic energy of 0.5 eV for Cl¯ in the process. Furthermore, in electron stimulated desorption (ESD) from CCl4…”

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confidence: 78%