Molecular clouds within 300 pc of the galactic center (GC) are known to
exhibit different physical properties and chemistry than those in the outer
Galaxy. High kinetic temperatures (>100K) well above the dust temperatures
are found in these molecular clouds. This rules out gas-dust collisions as
the main heating mechanism for the molecular clouds in the GC, so alternative
mechanisms which only act directly on the gas are required. Several heating
mechanisms have been proposed (UV radiation, enhanced flux of Cosmic Rays,
supersonic "turbulence" and ambipolar diffusion) but the lack of a detailed
knowledge of the properties of these clouds has prevented from drawing any
definite conclusions. We propose to make a detail investigation of the
physical conditions, namely the energetics, kinematics, ionization structure
and chemical composition of an unbiased sample of 30 molecular clouds in the
GC region by observing selected lines from key molecules (OH, CO, H2, CH,
HeH+) and neutral and ionized atoms (CII, OI, NII, SiI, SiII, SI, SIII and
NeII). These data will provide, for the first time, the abundance of those
species which will allow us to understand the energy balance (cooling and
heating) of molecular clouds in the GC. Our understanding of the properties
of molecular clouds in the center of the Galaxy is extremely important, with
this information for a nearby prototype, we have a unique comparison with
more distant galaxies for which our angular resolution and sensitivity are
inadequate.