15min:

PATRICK DUPRÉ, PATRICK RUPPER, SHENGHAI WU AND TERRY A. MILLER, Department of Chemistry, Ohio State University, 120 W. 18th Ave, Columbus OH, 43210.

The jet-cooled high resolution CRDS spectra of the methyl peroxy radical, CH₃ OO and CD₃ OO has been obtained for the weak A ²A^' X ²A^'' 0₀⁰ band. The rotational spectra of the isotopologue species exhibit very different structure. The hindered internal rotational involving methyl and O₂ groups is a source of this very different structure, due to the strong dependence of the tunneling splitting upon mass through the F parameter ( 4.4 cm^-1 for CD₃ OO compared to 7.0 cm^-1 for CH₃ OO). We will discuss the formalism in the limit of the high torsional barrier in the light of the experimental results, emphasizing the spectral resemblances and differences.