E u r o S c i C o n C o n f e r e n c e o n
Chemistry
2018
Chemistry 2018
Journal of Organic & Inorganic Chemistry
ISSN 2472-1123
F e b r u a r y 1 9 - 2 0 , 2 0 1 8
P a r i s , F r a n c e
Page 23
W
e classify macroscopic amounts of matter according to various
concepts, as metals, semiconductors, insulators, atoms, molecules,
complexes, polymers, and so on. Each of these terms triggers a specific
image that has a consistent meaning throughout the scientific community. But
which of these describe adequately an isolated nanocluster like Pt13? We use
Newtonian mechanics to describe the frictionless, periodic motion of a system
consisting of a few particles, and we can give trajectories and the momentum
of every particle at each instant of time. In contrast, systems consisting of
large numbers of particles are treated thermodynamically as ensembles
in which the information of individual particles is lost and available only as
a statistical average. Spontaneous processes occur under heat dissipation,
are not normally periodic and approach an equilibrium characterized by a
minimum in free energy. Is Newtonian mechanics or thermodynamics more
appropriate for treating nanoclusters? Many of the concepts that we use to
describe macroscopic amounts of matter break down for nanomaterials.
Metals turn into semiconductors and insulators; phase transition temperatures
shift dramatically, and the transitions broaden and disappear completely so
that the Gibbs phase rule loses its meaning. Heat and temperature that are
normally understood to represent kinetic energy are no longer well defined.
According to traditional definition we may find that a small system cools down
instead of heating up when we deposit more energy on it, pretending a negative
heat capacity. Small systems are getting increasingly relevant in chemistry and
physics, e.g. in catalysis, molecular electronics or energy devices. It is here
where one starts to find amazing and perhaps disturbing phenomena, and
these are becoming a hot field of research. Even in an expected thermodynamic
system one may find quantum phenomena. The question comes up how we
manage the transition between unexpectedly incompatible descriptions.
Biography
Emil Roduner studied Chemistry at the University of Zürich and
at the Rensselaer Polytechnic Institute in Troy, NY. In 1988, he
was awarded the Werner Prize by the Swiss Chemical Society
for developing muon spin resonance to a universal method
for studying structure and reaction behaviour of free radicals.
During 1995-2012 he held a Chair of Physical Chemistry at the
University of Stuttgart. After retirement he accepted a part-time
Professorship at the University of Pretoria in South Africa. He
wrote an advanced textbook,
“Nanoscopic Materials: Size-De-
pendent Phenomena and Growth Principles”
(RSC, 2014). His
research interests include studies on structure, size-effects and
magnetism of platinum nano-clusters and dynamics of mole-
cules in the pores of zeolites, mechanisms of elementary steps
in catalysis, kinetic isotope effects, degradation and proton
conductivity of fuel cell polymer membranes. In South Africa, he
is working on the electrochemical conversion of CO2 to liquid
fuels using solar energy.
e.Roduner@ipc.uni-stuttgart.deNanomaterials: in between traditional concepts of understanding
matter
Emil Roduner
University of Stuttgart, Germany
Emil Roduner, J Org Inorg Chem 2018, Volume: 4
DOI: 10.21767/2472-1123-C1-002