Angular and High-Frequency Analysis of Interference Structures in Electron Emission Spectra from 60 MeV/u Kr$^{34+}$ + H$_{2}$.*

New measurements of interference structures associated with electron emission have been made for 60 MeV/u Kr$^{34+}$ + H$_{2}$ collisions to characterize the angular dependence of the primary interference structures over a wide range including backward ejection angles, and, additionally, to search for high-frequency structures as reported for 1-5 MeV/u H$^{+}$ + H$_{2}$ collisions.$^{1}$ Comparison of the data with several theories over the range 30$^{o}$--150$^{o}$ shows the theories to follow the trend of the data but underestimate the measured oscillation frequencies by as much as 50{\%} for backward angles. High-statistics measurements of electron spectra for 90$^{o}$ and 150$^{o}$ were subjected to Fourier analysis to determine if components corresponding to high-frequencies exist in the inverse spectrum but no evidence was found, in contrast to the results reported for H$^{+}$ + H$_{2}$. $^{1}$S. Hossain \textit{et al}., Phys. Rev. A \textbf{72}, 010701(R) (2005)..