Rainbow Peaks Research Articles

The determination of potential-well depths directly from rainbow maxima

An empirical relationship is presented between the potential-well depth epsilon and the reduced rainbow peak angle tau M=E chi M in a Smith plot of molecular-beam differential-scattering data. This relationship permits determination of epsilon to within +or-5% directly from the data.

Crossed Beam Studies of Low Energy He+ Ions by He Atoms

Differential scattering of He+ ions by He atoms in the energy range of 10 to 100 eV over the scattering angle from 2° to 20° has been measured using the crossed beam apparatus. Prominent oscillatory structures in the differential cross section resulting from the interference between waves scattered from the lowest gerade 2Σg+ and ungerade 2Σu+ states of a pseudo-molecular ion He2+ were observed. The rainbow peak due to the elastic scattering of He+ by He was observed superimposingly upon these oscillatory structures due to the resonant electron capture. The relative differential cross sections were normalized to the absolute data of Lorents and Aberth.

Intermolecular Potentials from Differential Cross Sections: Ar + Ar

The angular distribution of Ar + Ar scattering at E = 9.16 × 10−14 erg was measured out to the rainbow pattern (supernumerary rainbow and part of the rainbow peak) by the crossed molecular beam technique, with mass spectrometric detection. This distribution was compared to calculated differential cross sections. Total cross sections, and spectroscopic constants for Ar2 were also calculated. The trial potentials were L.J.-12,6, LJ.-20,6, a modified Lennard–Jones potential (L.J.-14,12,8,6) and the Bobetic–Barker potential. The Bobetic–Barker potential is the one most consistent with cross section and spectroscopic experiments.