  Polymer translocation through a nano-pore in a thin membrane is studied using
a coarse-grained bead-spring model and Langevin dynamics simulation with a
particular emphasis to explore out of equilibrium characteristics of the
translocating chain. We analyze the out of equilibrium chain conformations both
at the $cis$ and the $trans$ side separately either as a function of the time
during the translocation process or as as function of the monomer index $m$
inside the pore. A detailed picture of translocation emerges by monitoring the
center of mass of the translocating chain, longitudinal and transverse
components of the gyration radii and the end to end vector. We observe that
polymer configurations at the $cis$ side are distinctly different from those at
the $trans$ side. During the translocation, and immediately afterwards, the
chain is clearly out of equilibrium, as different parts of the chain are
characterized by a series of effective Flory exponents. We further notice that
immediately after the translocation the last set of beads that have just
translocated take a relatively compact structure compared to the first set of
beads that translocated earlier, and the chain immediately after translocation
is described by an effective Flory exponent $0.45 \pm 0.01$. The analysis of
these results is further strengthened by looking at the conformations of chain
segments of equal length as they cross from the $cis$ to the $trans$ side, We
discuss implications of these results to the theoretical estimates and
numerical simulation studies of the translocation exponent reported by various
groups.
