Knowledge Bank

Pendular spectra of $HF-(o-H2)n(p-H2)m[n,m=0,6]$ van der Waals complexes in liquid helium droplets have been recorded. The compositions of the different complexes were determined by comparing pendular spectra taken with normal and para-enriched hydrogen. Field-free, rotationally resolved spectra were also obtained for the $(n,m)=(0,2),(1,1)$ and (2,0) complexes. The results have been used to draw inferences about the relative aggregation behaviors of ortho- and para-$H2$ with HF.