Riccardo Ferrando &
Francesca Baletto talk with ScienceWatch.com and
answer a few questions about this month's Emerging Research
Front Paper in the field of Chemistry. The authors
have also sent along images of their work.
Article: Structural properties of nanoclusters:
Energetic, thermodynamic, and kinetic
Journal: REV MOD PHYS, 77 (1): 371-423 JAN 2005
Addresses: Abdus Salam Int Ctr Theoret Phys, Strada
Costiera 11, I-34014 Trieste, Italy.
Univ Genoa, INFM, I-16146 Genoa, Italy.
Univ Genoa, Dipartimento Fis, I-16146 Genoa, Italy.
Why do you think your paper is highly
The pursuit of nanoscience and nanotechnology is in order to understand, control,
and manipulate objects of only a few nanometres size (1-100 nm), thus
comprising from a few atoms to several million. These objects, usually
called nanoclusters or nanoparticles, present peculiar chemical and
physical properties that are strongly dependent on the geometric
structure they assume.
These properties can be qualitatively different from those of their
elementary constituents (being either atoms or molecules) and of
macroscopic pieces of matter. Therefore, understanding from an atomistic
point of view, the conditions under which one structure is more probable
than another, is a real challenge. It involves a strong interplay of
experiment with theory and numerical simulation.
The high citation of our article is because it is a comprehensive work in
that direction. It especially focuses on how external parameters, such as
temperature and growth conditions, can influence the actual shape of a
nanoparticle. A detailed analysis of how transformations between different
structures can take place is discussed. In addition, we think that the
paper is highly cited also because it can serve as a reference work for
scientists entering and developing the field of research in nanoclusters.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
It was a mix of everything. As a review paper, we summarized the
state-of-the-art of this field, however, organizing the material from an
original perspective. On the other hand, we also discovered, in a series of
previous papers (see: F. Baletto, et al., "Reentrant morphology
transition in the growth of free silver nanoclusters," Phys. Rev.
Lett. 84 , 2000; F. Baletto, et al., "Evidence of
kinetic trapping in clusters of C60 molecules," Phys. Rev. Lett.
88 , 2002), the importance of kinetic effects to determine the
experimentally produced structures of nanoclusters. We singled out
structural transformations of general character, occurring by the same
mechanism in a variety of very different systems such as, for example,
clusters of silver or copper atoms and clusters of fullerene molecules.
Would you summarize the significance of your paper in
Nanoclusters are now becoming of widespread use in various applications,
ranging from medicine (DNA-sequencing), to memory storage (nano-magnets),
optics (quantum dots), and catalysis
(fuel cells). Such a wide range of applications is
possible because of the enormous variety of properties which are found
in nanoparticles of different sizes and made of different materials. The
properties of a nanoparticle are a consequence of its actual structure.
Our paper constitutes a reference work for the structural properties of
How did you become involved in this research and were
any particular problems encountered along the way?
We entered this research field in 1998, starting with the Ph.D. work of Dr.
Francesca Baletto in collaboration with Dr. Christine Mottet in Marseille,
at the Centre Interdisciplinaire de Nanoscience de Marseille (CINAM/CNRS).
The reason why we decided to enter the field was because we believed that
it could be a rapidly developing subject, with the potential of quite
exciting new physics at the borders of surface science, chemistry, and
Ten years ago, the field needed a joint effort of theory and experiment, so
the numerical methods would have been very useful to the interpretation of
experimental results. We developed our own numerical methodologies based on
molecular dynamics. Our simulations proved successful for the
interpretation of experimental results. Luckily we did not encounter any
particular difficulties in developing our work.
Where do you see your research leading in the
Our computational modelling research in nanoparticles is developing in the
direction of studying more and more realistic and reliable models of
systems of interest for technological applications. These systems range
from water clusters (M.S. Lee, et al., "Far-infrared absorption of
water clusters by first-principles molecular dynamics," J. Chem.
Phys. 128 , 2008), to bimetallic nanoparticles (C. Mottet,
et al., "Single impurity effect on the melting of nanoclusters,"
Phys. Rev. Lett. 95 , 2005; R. Ferrando, et al.,
"Nanoalloys: from theory to applications of alloy clusters and
nanoparticles," Chem. Rev. 108 , 2008), and surface-supported
clusters (R. Ferrando, et al., "Interface stabilized phases of
metal-on-oxide nanodots," ACS Nano, in press, DOI:
10.1021/nn800315x) for catalytic applications and memory storage, to
matrix-embedded metal clusters for applications in optics and plasmonics.
Do you foresee any social or political implications for
Our work is basic research in physics, with multidisciplinary aspects of
interest for chemistry and materials science. We would say that our work
has no direct social or political implications. However, research in
nanoclusters is a fundamental part of nanoscience and nanotechnology, which
already have a strong impact on our society.
Prof. Riccardo Ferrando
Dipartimento di Fisica
Università di Genova
Dr. Francesca Baletto
King's College London,