  We have mapped the large-scale structure of the Serpens cloud core using
moderately optically thick (13CO(1--0) and CS(2--1)) and optically thin tracers
(C18O(1--0), C34S(2--1), and N2H+(1--0)), using the 16-element focal plane
array operating at a wavelength of 3mm at the Five College Radio Astronomy
Observatory. Our main goal was to study the large-scale distribution of the
molecular gas in the Serpens region and to understand its relation with the
denser gas in the cloud cores, previously studied at high angular resolution.
All our molecular tracers show two main gas condensations, or sub-clumps,
roughly corresponding to the North-West and South-East clusters of
submillimeter continuum sources. We also carried out a kinematical study of the
Serpens cloud. The 13CO and C18O(1--0) maps of the centroid velocity show an
increasing, smooth gradient in velocity from East to West, which we think may
be caused by a global rotation of the Serpens molecular cloud whose rotation
axis is roughly aligned in the SN direction. Although it appears that the cloud
angular momentum is not sufficient for being dynamically important in the
global evolution of the cluster, the fact that the observed molecular outflows
are roughly aligned with it may suggest a link between the large-scale angular
momentum and the circumstellar disks around individual protostars in the
cluster. We also used the normalized centroid velocity difference as an infall
indicator. We find two large regions of the map, approximately coincident with
the SE and NW sub-clumps, which are undergoing an infalling motion. Although
our evidence is not conclusive, our data appear to be in qualitative agreement
with the expectation of a slow contraction followed by a rapid and highly
efficient star formation phase in localized high density regions.
