Cartan Angular Invariant and Deformations in Rank One Symmetric Spaces
  We develop and study quaternionic and octonionic analogies of Cartan angular and Toledo invariants that are well known in the complex hyperbolic space. Using such invariants we study quasifuchsian deformations (including bendings) of quaternionic and octonionic hyperbolic manifolds. 
Boris Apanasov and Inkang Kim