NOTE: Hydrogen Dimer Features in the 2-μm Spectra of Saturn and Neptune

We report the detection of the (H₂)₂dimer in the atmospheres of Saturn and Neptune based on spectra of the fundamentalS₁(1) collision-induced band of H₂. The lines of this dimer are potentially useful for probing the (H₂)₂ortho-para ratio and its implications for atmospheric dynamical processes. We also report the detection of the (1-0)S₁(1) quadrupole absorption line of monomeric H₂in these spectra.