  The precise control and knowledge over the atomic dynamics is central to the
advancement of quantum technology. The different experimental conditions
namely, atoms in a vacuum, an anti-relaxation coated and a buffer gas filled
atomic cell provides complementary platform for such investigations. The extent
of changes in optical pumping, velocity changing collision and hyperfine
changing collision rates associated with these conditions are discussed. There
is a phenomenal change in the optical density by a factor of >25 times in
presence of a control field in buffer gas environment. In contrary to earlier
reports, we found confinement induced enhanced optical pumping as the mechanism
behind the observed transparency in buffer gas cell. The feeble interplay of
radiation trapping under specific conditions are pointed out. The diffusive
velocity of atoms is measured to be ~25+-12 m/s and <= 8+-4 m/s for
anti-relaxation coated and buffer gas filled cell respectively. The studies
will have useful application in measurements of relaxation rates, quantum
memory, quantum repeaters and atomic devices.
