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     COLLOQUIUM OF THE COMPUTATIONAL MATERIALS SCIENCE CENTER
AND THE SCHOOL OF PHYSICS, ASTRONOMY, & COMPUTATIONAL SCIENCES
               (CSI 898-Sec 001 crosslisted with PHYS 703)
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      Beyond The Periodic Table of Elements: Role of Superatoms

                               Puru Jena
  Department of Physics, Virginia Commonwealth University, Richmond, VA

Of the 90 elements in the periodic table that occur in nature, some are
abundant while some others are scarce. Replacing these scarce elements with
earth-abundant elements is an important challenge for materials science and
society. Novel properties of matter at the nanoscale and the prospect of
tailoring them by manipulating size, shape, and composition, one atom at a
time, have led to the hope that nanoparticles of earth-abundant materials can
be used to replace some of the scarce elements. Nearly twenty years we showed
that stable atomic clusters with specific size and composition and mimicking
the chemistry of atoms in the periodic table can be designed and synthesized.
These clusters known as “superatoms” can then form the building blocks of a
new three-dimensional periodic table and hence, a new class of
cluster-assembled materials.  

This talk will outline the considerable progress that has been made over
the years by focusing on one class of “superatoms” called “superhalogens”.
Conventional superhalogens consist of a metal atom at the core surrounded by
halogen atoms and have electron affinities far exceeding those of halogen
atoms. Because of their high electron affinities, superhalogens almost always
exist as negative ions, usually as the anionic portions of salts. While past
studies have revealed many such molecules like permanganates and perchlorates,
many more are waiting to be discovered. I will also report on the discovery of
an entirely new class of superhalogens with unusual composition and properties
and show how simple electron counting rules, such as the octet, 18-electron,
and Wade-Mingos rule can be used to facilitate such discovery. Ways in which
these man-made “elements” can potentially alter properties of materials will
be presented.

                            April 7, 2014
                               4:30 pm
                    Room 3301, Exploratory Hall, Fairfax Campus

Refreshments will be served at 4:15 PM.
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Find the schedule at http://www.cmasc.gmu.edu/seminars.htm