Far Ultraviolet Spectroscopic Explorer ( FUSE ) data is used to investigate the molecular hydrogen ( H _ { 2 } ) content of intermediate-velocity clouds ( IVCs ) in the lower halo of the Milky Way .
We analyze interstellar absorption towards 56 ( mostly extragalactic ) background sources to study H _ { 2 } absorption in the Lyman- and Werner bands in 61 IVC components at H i column densities \geq 10 ^ { 19 } cm ^ { -2 } .
For data with good S/N ( \sim 9 per resolution element and higher ) , H _ { 2 } in IVC gas is convincingly detected in 14 cases at column densities varying between \sim 10 ^ { 14 } and \sim 10 ^ { 17 } cm ^ { -2 } .
We find an additional 17 possible H _ { 2 } detections in IVCs in FUSE spectra with lower S/N .
The molecular hydrogen fractions , f , vary between 10 ^ { -6 } and 10 ^ { -3 } , implying a dense , mostly neutral gas phase that is probably related to the Cold Neutral Medium ( CNM ) in these clouds .
If the H _ { 2 } stays in formation-dissociation equlibrium , the CNM in these clouds can be characterized by compact ( D \sim 0.1 pc ) filaments with volume densities on the order of n _ { H } \sim 30 cm ^ { -3 } .
The relatively high detection rate of H _ { 2 } in IVC gas implies that the CNM in these clouds is ubiquitous .
More dense regions with much higher molecular fractions may exist , but it would be difficult to detect them in absorption because of their small size .