Hydroxyl, water, ammonia, carbon monoxide and neutral carbon towards the
  Sgr A complex
  We observed OH, H$_2$O, HN$_3$, C$^{18}$O, and C$_I$ towards the +50 km/s
cloud (M-0.02-0.07), the CND and the +20 km/s (M-0.13-0.08) cloud in the Sgr A
complex with the VLA, Odin and SEST. Strong OH absorption, H$_2$O emission and
absorption lines were seen at all three positions. Strong C$^{18}$O emissions
were seen towards the +50 and +20 km/s clouds. The CND is rich in H$_2$O and
OH, and these abundances are considerably higher than in the surrounding
clouds, indicating that shocks, star formation and clump collisions prevail in
those objects. A comparison with the literature reveals that it is likely that
PDR chemistry including grain surface reactions, and perhaps also the
influences of shocks has led to the observed abundances of the observed
molecular species studied here. In the redward high-velocity line wings of both
the +50 and +20 km/s clouds and the CND, the very high H$_2$O abundances are
suggested to be caused by the combined action of shock desorption from icy
grain mantles and high-temperature, gas-phase shock chemistry. Only three of
the molecules are briefly discussed here. For OH and H$_2$O three of the nine
observed positions are shown, while a map of the C$^{18}$O emission is
provided. An extensive paper was recently published with Open Access (Karlsson
et al. 2013; http://www.aanda.org/articles/aa/pdf/2013/06/aa20471-12.pdf ).
