Die kinetische Energie ionisierter Molekülfragmente. II. Untersuchungen an einfachen Paraffinen

Abstract

The deflection method has been used to measure the initial energy distribution functions WE of nearly all fragment ions from methane, ethane, propane, both butanes and in addition of some ions from pentanes and hexanes at an electron energy of 75 eV. The results of these experiments can be condensed into the following rules: 1) The initial energy distributions of ions which have lost only H-atoms do not show any structure. The shape of these distributions may be called quasithermal. The average kinetic energy of ions with a quasithermal distribution is monotonically increasing with the number of C - H bonds to be broken during the formation of the respective ion. 2) The distributions of ions which have lost one or more but not all C-atoms, normally consist of a quasithermal group and a so called satellite group of rather high kinetic energy. The CH₃₊ satellites are well known examples. For a certain compound the satellite groups of ions with the same C-number have nearly equal average kinetic energy. On mass number 28 of the butanes, n-pentane and n-hexane and on mass number 42 of n-hexane two satellites are observed. 3) The initial energy distributions of H⁺ and H₂ ⁺ originating from paraffin molecules show pronounced structure.