  We develop some methods to compute the Makar-Limanov and Derksen invariants,
isomorphism classes and automorphism groups for k-domains B, which are
constructed from certain Russell k-domains. We propose tools and techniques to
distinguish between k-domains with the same Makar-Limanov and Derksen
invariants. In particular, we introduce the exponential chain associated to
certain modifications. We extract C-domains from the class B that have smooth
contractible factorial Spec(B), which are diffeomorphic to R 6 but not
isomorphic to C 3, that is, exotic C 3. We examine associated exponential
chains to prove that exotic threefolds Spec(B) are not isomorphic to Spec(R),
for any Russell C-domain R.
