Chapter 4 - Relativistic Effects on NMR Parameters

Abstract

For heavy atoms, and for molecules with heavy atoms, a theoretical description of the electronic structure needs to consider the finite speed of light and Einstein’s special relativity. This chapter provides a brief introduction to special relativity and to relativistic methods in quantum chemistry. It is shown how these methods can be used to calculate NMR chemical shifts and indirect spin–spin coupling constants (J-coupling). A number of examples are discussed where relativistic effects have a significant influence on these NMR parameters. In some cases for example, for indirect spin–spin coupling involving 199Hg, relativistic effects may be larger than the total value calculated with a nonrelativistic method.