  This paper presents a detailed study of the chemistry in the outflow
associated with the low-mass protostar NGC1333-IRAS2A down to 3" (650 AU)
scales. Millimeter-wavelength aperture-synthesis observations from the OVRO and
BIMA interferometers and (sub)millimeter single-dish observations from the
Onsala 20m telescope and CSO are presented. The interaction of the highly
collimated protostellar outflow with a molecular condensation ~15000 AU from
the central protostar is clearly traced by molecular species such as HCN, SiO,
SO, CS, and CH3OH. Especially SiO traces a narrow high velocity component at
the interface between the outflow and the molecular condensation.
Multi-transition single-dish observations are used to distinguish the chemistry
of the shock from that of the molecular condensation and to address the
physical conditions therein. Statistical equilibrium calculations reveal
temperatures of 20 and 70 K for the quiescent and shocked components,
respectively, and densities near 10^6 cm^{-3}. Significant abundance
enhancements of two to four orders of magnitude are found in the shocked region
for molecules such as CH3OH, SiO and the sulfur-bearing molecules. HCO+ is seen
only in the aftermath of the shock consistent with models where it is destroyed
through release of H2O from grain mantles in the shock. N2H+ shows narrow
lines, not affected by the outflow but rather probing the ambient cloud.
Differences in abundances of HCN, H2CO and CS are seen between different
outflow regions and are suggested to be related to differences in the atomic
carbon abundance. Compared to the warm inner parts of protostellar envelopes,
higher abundances of in particular CH3OH and SiO are found in the outflows,
which may be related to density differences between the regions.
