Hi Sashikiran,
You could use the Python toolkit to do the conversion.
The code would be something like:
rd = ReMDocument(atom_doc)
ap = AtomParser()
rem = ap.parse(rd)
srlz = RdfLibSerializer('pretty-xml')
rem2 = rem.aggregation.register_serialization(srlz)
rd2 = rem2.get_serialization()
print rd2.data
HTH
Rob