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<br>
<div align="center"><font size=5><b>Jueves 6 de marzo de 2008 - 13
hs<br><br>
</b>Aula de Seminarios del INQUIMAE, 3er piso Pab. II <br><br>
<br><br>
</font><font size=6><b>Prof. Antonio Sgamellotti<br>
</font><font size=4><i>Dipartimento di Chimica, CNR-ISTM and UdR
INSTM<br>
University of Perugia, Via Elce di Sotto 8, 06123 Perugia<br><br>
<br><br>
</i></font><font size=5>THEORETICAL INVESTIGATIONS ON CARBON NANOTUBES:
SIDEWALL FUNCTIONALIZATION AND ENCAPSULATION OF NANOCRYSTALLITES<br><br>
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Abstract:<br>
The investigation of nanostructured systems and materials is currently a
topic of great interest, in view of future technological applications. In
this field modelling plays an important role; theoretical calculations
provide insight into the microscopic properties and behaviour of these
systems. In this work we present theoretical investigations on the
properties of carbon nanotubes (CNTs), one of the most studied and
promising species in the field of nanotechnology.<br>
The chemical functionalization of CNTs represents an attractive target
for study, since it can improve their solubility and processability.
Accurate theoretical investigations of functionalized CNT may clarify the
effects of chemical modifications on their electronic and structural
properties. Static and dynamical density functional theory calculations
have been performed to analyze the interaction of different species with
CNTs. The areas of applications considered in this work include several
functionalization routes and related properties. As a first example,
investigations have concerned the functionalization of CNTs with
transition metal complexes, which is found to affect the electronic
properties of the adduct. Moreover, the interaction between small
molecules and the CNT sidewall has been analyzed in order to investigate
eventual technological applications of CNTs in fields like gas-sensing or
hydrogen storage in nanostructured fuel cells. In all cases, special
attention has been devoted to the definition of proper models for the
sidewall, which constitute a mandatory step to achieve the required
accuracy.<br>
Another field of investigation has concerned the confined growth of ionic
species by encapsulation in CNTs, which has recently attracted growing
interest. The ability to encapsulate different materials has indeed
constituted one of the first applications of CNTs. Besides the
possibility of creating intrinsically monodimensional materials through
nanotube-driven template syntheses, one of the most interesting aspects
of encapsulation concerns the formation of ordered structures in the
hollow of CNTs, in the form of nanocrystallytes. The one-dimensional
confined growth of different compounds has been viewed as a suitable
route to the development of new low-dimensional materials, like
nanowires. In our work, the morphologies of AgI nanocrystallites grown
inside (n,n) single-walled CNTs are investigated by means of molecular
dynamics simulations. All crystal structures found are formally
constituted by (n,m) AgI nanotubes, with chiral vectors n and m depending
on the CNT diamenter and on the local environment. In particular, for
narrow CNTs unprecedented low-dimensional AgI nanoribbons appear,
actively stabilized by a deformation of the CNT, as observed in
experiments. In larger diameter CNTs, inorganic (n,m) AgI nanotubes are
typically formed, giving rise to a scenario of polymorphism in the
nanoregime.<br>
An extention of the Clar sextet theory of aromatic systems is proposed
for finite-length models of metallic and semiconducting carbon nanotubes
(CNTs). For metallic CNTs, the electronic properties of finite-length
models converge monotonically to the values expected for
quasi-monodimensional metallic systems. For semiconducting CNTs, the use
of finite-length models leads to a fast convergence of the electronic
properties to the values expected for the corresponding infinite
nanotube.<br><br>
Curriculum vitae<br><br>
Full Professor of Inorganic Chemistry, University of Perugia, since the
1st November 1975.<br>
Member of the National Chemistry Committee of the CNR Italian Research
Council (1988-1994).<br>
Coordinator of the Institutional Fellowship (Perugia, Heidelberg,
Lausanne) of the Human Capital and Mobility (1992-1994).<br>
Chairman of the CERC3 (Chairmen of the European Research Councils
Chemistry Committees) (1992-1994).<br>
Responsible of International Collaborative Research Projects with the
Universities of Heidelberg, Lausanne, Durham and with the Daresbury
Laboratory.<br>
Member of the Steering Committee of the ESF (European Science Foundation)
scientific program "Relativistic effects in heavy element chemistry
and physics".<br>
Member of the scientific committee of CECAM (Centre Europeen de Calcul
Atomique et Molèculaire).<br>
Italian representative of the European COST project on Chemistry.
Chairman of the Management Committee of the COST Action D3 "Theory
and modelling of chemical systems and processes" (1992-1994).<br>
Coordinator of the COST Chemistry Project D3/0002/92 and D9/0005/97
(Perugia, Lausanne, Heidelberg, Daresbury) (1992-1995).<br>
Chairman of the Scientific Committee of the PQE2000 (for high performance
computing), with the involvement of CNR, INFN, ENEA, QSW (Alenia
Spazio/MEIKO).<br>
Member of the EC evaluation panel "Large Scale Facilities"<br>
President of the Centre of the Excellence SMAArt "Scientific
Methodologies applied to Archaeology and Art" approved and financed
by Murst the 2nd April 2001, at the University of Perugia.<br>
Member of the CNR Executive Committee (1999-2003).<br>
Member of G8 panel on "Research Assessment".<br>
Member of the panel on "Materials" at the ESRF Grenoble.<br>
External Advisor of the ERA-NET CHEMISTRY<br>
National Coordinator of the "Cultural Heritage" Group of INSTM
(National Consortium of Materials Science and Technology)<br>
Partner of European Project LabS TECH (Laboratories on Science and
Technology for the conservation of European Cultural Heritage) (5° P.Q.)
and Eu-ARTECH (Access, Research and Technology for the conservation of
the European Cultural Heritage) (6°P.Q.)<br>
Chairman of the committee for the University degree in "Sciences and
Technologies for the Conservation and Restoration of the Cultural
Heritage" <br>
Author of about 300 scientific publications in international journals
concerning advanced computations on chemistry, electronic and structural
properties of molecules and inorganic materials, spectroscopic properties
and characterization of archaeological and art-historical artefacts.<br>
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