  Over the last 3 yrs, the Galactic center (GC) region has been monitored with
the Chandra X-Ray Observatory. With 11 Chandra observations through 2002 June,
the total effective exposure reaches ~590 ks, providing significant photon
statistics on the faint, filamentary, diffuse X-ray emission. The true-color
X-ray image and the equivalent width (EW) images for the detected elemental
species demonstrate that the diffuse X-ray features have a broad range of
spatio-spectral properties. Enhancements of the low-ionization-state, or
``neutral'' Fe line emission (E~6.4 keV) to the northeast of Sgr A* can be
interpreted as fluorescence within the dense ISM resulting from irradiation by
hard, external X-ray sources. They may also be explained by emission induced by
the bombardments by high energy particles on the ISM, such as unresolved
supernova (SN) ejecta intruding into dense ISM. The detection of molecular
cloud counterparts to the 6.4 keV Fe line features indicates that these Fe line
features are associated with dense GC clouds and/or active star-forming
regions, which supports the X-ray reflection and/or SN ejecta origins for the
Fe line emission. We detect highly ionized S and Si lines which are generally
coincident with the neutral Fe line emission and the dense molecular clouds in
the northeast of Sgr A*. These hot plasmas are likely produced by massive
star-forming activities and/or SNRs. In contrast, we find that highly ionized
He-like Fe line emission (E~6.7 keV) is primarily distributed along the plane
instead of being concentrated in the northeast of Sgr A*. The implied high
temperature and the alignment along the plane are consistent with the magnetic
confinement model.
