High-Resolution Infrared Spectroscopy of Solid Hydrogen: The Tetrahexacontapole-InducedΔJ=6Transitions

Weak new features in the absorption spectrum of solid hydrogen were observed by high-resolution infrared spectroscopy, and assigned as transitions with total change in angular momentum of $\Delta J=6\mathrm{}$. The tetrahexacontapole (64-pole)-induced rotational transition $W_0\mathrm{}\left(0\right)\mathrm{}$ was studied with a difference frequency laser spectrometer and found to be very narrow, with a linewidth of 0.003 ${\mathrm{cm}}^{-1\mathrm{}}$ HWHM in 99.8% parahydrogen. Frequencies, linewidths, and integrated absorption strengths were measured for several pure rotational and rotation-vibration transitions from 1800 to 7000 ${\mathrm{cm}}^{-1\mathrm{}}$, and the tetrahexacontapole moment was determined.