  High-order harmonic generation (HHG) in aligned linear molecules can offer
valuable information about strong-field interactions in lower-lying molecular
orbitals, but extracting this information is difficult for three-dimensional
molecular geometries. Our measurements of the asymmetric top SO2 show large
axis dependencies, which change with harmonic order. The analysis shows that
these spectral features must be due to field ionization and recombination from
multiple orbitals during HHG. We expect that HHG can probe orbital dependencies
using this approach for a broad class of asymmetric-top molecules.
