A new relativistic theory: a relativistic scheme by eliminating small components (RESC)

A new relativistic theory has been proposed by the elimination of small components of the Dirac equation. It is variationally stable and can easily be incorporated into any electronic structure theory. The present formalism is tested in standard problems of Ag and Au atoms and their hydrides at various levels of theory including single- and multi-reference-based methods. Numerical results show that good accuracy can be obtained.