  Using a sample of 38 radio-loud galaxy mergers at z<=0.2, we confirm the high
detection rate (~84%) of HI 21-cm absorption in mergers, which is significantly
higher (~4 times) than in non-mergers. The distributions of the HI column
density [N(HI)] and velocity shift of the absorption with respect to the
systemic redshift of the galaxy hosting the radio source in mergers are
significantly different from that in non-mergers. We investigate the connection
of the nuclear HI gas with various multi-wavelength properties of the mergers.
While the inferred N(HI) and gas kinematics do not show strong (i.e. >=3-sigma
level) correlation with galaxy properties, we find that the incidence and N(HI)
of absorption tend to be slightly higher at smaller projected separations
between the galaxy pairs and among the lower stellar mass-radio galaxies. The
incidence, N(HI) and line width of HI absorption increase from the pre-merger
to the post-merger stages. The 100% detection rate in post-mergers indicates
that the neutral gas in the circumnuclear regions survives the coalescence
period and is not yet quenched by the nuclear radio activity.

Astrophysics of Galaxies;Cosmology and Nongalactic Astrophysics