  The isothermal, isobaric spontaneous crystallization of a supercooled polymer
melt is investigated by MD simulation of an ensemble of fully-flexible linear
chains. Frustration is introduced via two incommensurate length scales set by
the bond length and the position of the minimum of the non-bonding potential.
Marked polymorphism with considerable bond disorder, distortions of both the
local packing and the global monomer arrangements is observed. The analyses in
terms of: i) orientational order parameters characterizing the global and the
local order and ii) the angular distribution of the next-nearest neighbors of a
monomer reach the conclusion that the polymorphs are arranged in distorted
Bcc-like lattices.
