  We propose using radio line spectroscopy to detect molecular absorption lines
(such as OH at 1.6-1.7 GHz) before and after the total eclipse of black widow
(BW) and other short orbital period binary pulsars with low mass companions.
The companion in such a binary may be ablated away by energetic particles and
high energy radiation produced by the pulsar wind. The observations will probe
the eclipsing wind being ablated by the pulsar and constrain the nature of the
companion and its surroundings. Maser emission from the interstellar medium
stimulated by a pulsar beam might also be detected from the intrabinary medium.
The short temporal resolution allowed by the millisecond pulsars can probe this
medium with the high angular resolution of the pulsar beam.
