Integrability of the D-n(2) vertex models with open boundary

We investigate various aspects of the integrability of the vertex models as sociated to the D-n(2) affine Lie algebra with open boundaries. We first st udy the solutions of the corresponding reflection equation compatible with the minimal symmetry of this system. We find three classes of general solut ions, one diagonal solution and two non-diagonal families with a free param eter. Next we perform the Bethe ansatz analysis for some of the associated open D-2(2) spin chains and we identify the boundary having quantum group i nvariance. We also discuss a new D-2(2) R-matrix. (C) 2000 Elsevier Science B.V. All rights reserved.