  Many investigations shed light on various correlations between structure and
dynamics in supercooled liquids; however, a general relation between structure
and dynamics remains elusive. This molecular dynamics simulation study
identifies the interrelationship between the growth of the highest peak of the
radial distribution function, variation in the radial force from this peak, and
the slowdown of the density relaxation in the supercooled states of a model
binary glass former. From the microscopic string-like motion in supercooled
liquids, we argue that the surface density on a spherical shell around a
reference particle at the highest peak of the radial distribution function can
represent the free volume available for motion. We further show from these
arguments and simulations that density relaxtion time and local density are
connected; in this expression, the dynamics diverge at a higher critical value
of local density. This relation is similar to the Vogel Fulcher Tammann
relation in supercooled liquids, thus giving insight into the structural origin
of the VFT as the jamming of particles in a channel of density relaxation.
