  Atomic Kapitza-Dirac (KD) scattering in the classical standing wave of lights
is widely used to make the laser-pulsed atom interferometers. In this
theoretical work, we show that the dielectric nanoparticle can be used as a
weak light source to generate atomic KD scattering and make atom
interferometer. We consider a cavity system consisting of atoms and a single
nanoparticle, where the nanoparticle is illuminated by the external laser
pulses. Atoms and the cavity mirrors are not illuminated by the laser beam, so
nanoparticle acts as a pulsed source to excite the cavity mode which
non-resonantly excites atomic internal state and generates a weak KD scattering
of atomic external motion. We use twice such scattering to split atomic path
and consequently use two classical laser pulses to recombine the separated
paths for generating the Ramsey-Bord\'{e} atom interferometer. This atom
interferometer is entangled with the centre-of-mass motion of nanoparticle and
could be developed to search the small nonclassicality of motional
nanoparticle, because the cavity mode excitation is associated with
nanoparticle's position relative to the node or antinode of that optical mode.
