Quantum mechanics provides the fundamental theoretical apparatus for
describing the structure and properties of atoms and molecules in terms
of the behaviour of their fundamental components, electrons and nudeL
For heavy atoms and molecules containing them, the electrons can move at
speeds which represent a substantial fraction of the speed of light, and
thus relativity must be taken into account. Relativistic quantum
mechanics therefore provides the basic formalism for calculating the
properties of heavy-atom systems. The purpose of this book is to provide
a detailed description of the application of relativistic quantum
mechanics to the many-body prob- lem in the theoretical chemistry and
physics of heavy and superheavy elements. Recent years have witnessed a
continued and growing interest in relativistic quantum chemical methods
and the associated computa- tional algorithms which facilitate their
application. This interest is fu- elled by the need to develop robust,
yet efficient theoretical approaches, together with efficient
algorithms, which can be applied to atoms in the lower part of the
Periodic Table and, more particularly, molecules and molecular entities
containing such atoms. Such relativistic theories and computational
algorithms are an essential ingredient for the description of heavy
element chemistry, becoming even more important in the case of
superheavy elements. They are destined to become an indispensable tool
in the quantum chemist's armoury. Indeed, since relativity influences
the structure of every atom in the Periodic Table, relativistic
molecular structure methods may replace in many applications the
non-relativistic techniques widely used in contemporary research.
