Radiolysis of Methane in a Wide‐Range Radiolysis Source of a Mass Spectrometer. I. Individual and Total Cross Sections for the Production of Positive Ions, Negative Ions, and Free Radicals by Electrons

The abundances of, and the total and individual cross sections for, primary products (positive ions, neutral species, and negative ions) resulting from elementary reactions induced by the absorption of energy by CH4 from ionizing radiation (100‐eV electrons) have been measured. This was accomplished with the dual electron beam section of our wide‐range radiolysis source. The results show that positive ions and free radicals are produced in nearly equal abundances, 45% and 55%, respectively. On the other hand, negative ions are less abundant by about four orders of magnitude. The total cross section for positive ionization (σI) by 100‐eV electrons is 3.8×10−16 cm2 and that for the formation of neutral species (σN) is 4.7×10−16 cm2. To independently test the reliability of the dual electron‐beam ion source, the total and individual cross sections for ionization of Ar by 100‐eV electrons were measured for comparison with published values. Our value for the total cross section (σI) of 3.24× 10−16 cm2 is in sa...

[1]  C. E. Melton,et al.  Experimental and Theoretical Considerations for Ionization of Simple Hydrocarbons, H2, D2, O2, H2O, and the Rare Gases by 2.2‐MeV α Particles and by Electrons in a Mass Spectrometer , 1966 .

[2]  B. Schram,et al.  Partial Ionization Cross Sections of He, Ne, H2, and CH4 for Electrons from 20 to 500 eV , 1966 .

[3]  C. E. Melton.  STUDY BY MASS SPECTROMETRY OF THE DECOMPOSITION OF AMMONIA BY IONIZING RADIATION IN A WIDE-RANGE RADIOLYSIS SOURCE. , 1966 .

[4]  C. E. Melton.  High transmission and dual electron beam ion sources for mass spectrometry , 1966 .

[5]  D. Rapp,et al.  Total Cross Sections for Ionization and Attachment in Gases by Electron Impact. I. Positive Ionization , 1965 .

[6]  D. Rapp,et al.  Cross Sections for Dissociative Ionization of Molecules by Electron Impact , 1965 .

[7]  C. E. Melton,et al.  Ionization Potentials of Alkyl Free Radicals and of Benzene, Toluene, and Triethylamine by the RPD Technique , 1964 .

[8]  C. E. Melton,et al.  APPEARANCE POTENTIALS OF POSITIVE AND NEGATIVE IONS BY MASS SPECTROMETRY , 1964 .

[9]  P. Kebarle,et al.  Ionization and Fragmentation of Some Molecules by High‐Energy Electrons , 1962 .

[10]  J. Craggs,et al.  Cross Sections for Ionization of the Inert Gases by Electron Impact , 1960 .

[11]  B. A. Tozek.  Measurements of Ionization Cross Sections for Electron Impactr I: Technique and Data for Methane† , 1958 .

[12]  F. W. Lampe,et al.  Cross Sections for Ionization by Electrons , 1957 .

[13]  J. W. Otvos,et al.  Cross-sections of Molecules for Ionization by Electrons , 1956 .

[14]  Philip T. Smith.  The Ionization of Helium, Neon, and Argon by Electron Impact , 1930 .

[15]  W. Bleakney.  Ionization Potentials and Probabilities for the Formation of Multiply Charged Ions in Helium, Neon and Argon , 1930 .

[16]  A. Hughes,et al.  Ionization of Gases as a Function of the Energy of Electron Impacts , 1924 .