Differential Cross Sections for the Scattering of CCl4 by Isooctane

Differential cross sections for the scattering of CCl₄ by isooctane (2,2,4‐trimethylpentane) are reported for the range of relative kinetic energy $Ē$ between 1.80 and 26.8 kcal mole⁻¹. The faster beams are produced by adding the CCl₄ to an excess of He which accelerates the heavier CCl₄ molecules as the mixture flows from the source. The velocity selector has disks with narrow slots produced by chemical etching. The scattered CCl₄ molecules are detected by their formation of negative ions at a hot Nb surface. The scattering at the higher energies shows rainbow structure which is used to determine parameters for an assumed form of the interaction potential. The disappearance of the rainbow maximum at low energies, attributed to the onset of orbiting, and the values of parameters derived indicate that the potential has a large central core. The decrease in the measured differential cross section at large angles implies the presence of a substantial amount of inelastic scattering.