Spectral-Line Survey at Millimeter and Submillimeter Wavelengths toward
  an Outflow-Shocked Region, OMC 2-FIR 4
  We performed the first spectral-line survey at 82--106 GHz and 335--355 GHz
toward the outflow-shocked region, OMC 2-FIR 4, the outflow driving source, FIR
3, and the northern outflow lobe, FIR 3N. We detected 120 lines of 20 molecular
species. The line profiles are found to be classifiable into two types: one is
a single Gaussian component with a narrow ($<$ 3 km s$^{-1}$) width and another
is two Gaussian components with narrow and wide ($>$ 3km s$^{-1}$) widths. The
narrow components for the most of the lines are detected at all positions,
suggesting that they trace the ambient dense gas. For CO, CS, HCN, and
HCO$^{+}$, the wide components are detected at all positions, suggesting the
outflow origin. The wide components of C$^{34}$S, SO, SiO, H$^{13}$CN,
HC$^{15}$N, H$_2^{13}$CO, H$_2$CS, HC$_3$N, and CH$_3$OH are detected only at
FIR 4, suggesting the outflow-shocked gas origin. The rotation diagram analysis
revealed that the narrow components of C$_2$H and H$^{13}$CO$^+$ show low
temperatures of 12.5$\pm$1.4 K, while the wide components show high
temperatures of 20--70 K. This supports our interpretation that the wide
components trace the outflow and/or outflow-shocked gas. We compared observed
molecular abundances relative to H$^{13}$CO$^+$ with those of the
outflow-shocked region, L1157 B1, and the hot corino, IRAS 16293-2422. Although
we cannot exclude a possibility that the chemical enrichment in FIR 4 is caused
by the hot core chemistry, the chemical compositions in FIR 4 are more similar
to those in L1157 B1 than those in IRAS 16293-2422.
