Relativistic Effects in Superheavy Elements
Peter Schwerdtfeger and Michael Seth
Department of Chemistry, University of Auckland,
Private Bag 92019, Auckland, New Zealand
Relativistic effects scale approximately with Z^2 (Z = nuclear charge),
hence very large relativistic effects are expected for the trans-actinides,
the elements beyond nuclear charge 103, the so-called superheavy elements.
The heaviest element discovered so far is the superheavy element 112 with
a half-life of only about 400 ms for the isotope 277. For chemical studies
at an atom-at-a-time scale half-lives within at least the second range are
required. Currently, this limits chemical applications to the elements up
to nuclear charge 106. On the other hand, the synthesis of more neutron-rich
elements near the double-magic number of protons and neutrons, the island of
stability with Z=114 and N=184, may produce elements with half-lives for any
radioactive decay lying well above the second range. A major drawback in the
synthesis is the small production cross section which drops rapidly with
increasing nuclear charge. Thus, for the prediction of periodic trends and the
chemical behaviour for elements including the 7th period of the periodic table
and beyond, the use of theoretical methods are currently the only way to gain
useful chemical information. This talk gives an overview on properties for
the elements with nuclear charge 111 to 119. It is shown that relativistic
effects significantly influence chemical properties of these elements.