That lens is highly specialised, Applied Photography, Focal Press, says that the 8-14 microns transmission band is used for thermal imaging of bodies too cool to emit near infra red. There's 3 other ranges 1.4 -1.9, 2.0 - 2.6 and 1.9 - 4.3 microns

0.3 - 1.38 microns covers the UV and visible light range as well as photographic infrared.

This lens isn't for film use it would have been used with some type photo cathode amplification device. Lenses like this are still made around the world and you can get a camera and lens for less than the asking price of this particular lens, it'll be digital though.

Pentax made a Nocta, ifra-red film camera,

Ian