- Alberto Modelli, born in Conselice (Ravenna), Italy, on June
- Position: Associate Professor, Department of Chemistry,
University of Bologna, via Selmi 2, 40126
- Teaching: Physical Chemistry (for the degree in Environmental
- University Degree (Title): Doctor in Chemistry, University of
Bologna, July 1974.
- Member of the Italian Society of Chemistry.
- Postdocs: University of Nebraska, Lincoln (USA), Department of
Physics and Astronomy,
March-September 1980 (with a N.A.T.O. grant).
- Visiting Professor Stays: University of Paris (France),
Physical Chemistry Institute "Pierre et Marie Curie", May-June
- Research consultant at CNR (Consiglio Nazionale delle
Ricerche) from 1981 to 2006.
The research activity is
devoted to the study of electronic structures, orbital interactions
and nature of chemical bonds in gas-phase molecular systems.
Various electron spectroscopy techniques are used: photoelectron
spectroscopy (PES, excited by X or UV radiations) supplies the
ionization energy values from the filled orbitals, electron
transmission spectroscopy (ETS) supplies the energies of electron
attachment to empty orbitals, that is, the negative of the vertical
electron affinity values, dissociative electron attachment
spectroscopy (DEAS) measures the abundance of negative fragments
produced by electron impact, as a function of the incident electron
energy. The experimental data are interpreted with the aid of
proper theoretical calculations.
A complete picture of the
electronic structure requires the knowledge of both the filled and
the empty levels, equally important from the thoretical and the
reactivity points of view. However, while ionization energy data
are easily available in the literature, the complementary electron
affinity data are still sparse. The ETS/DEAS apparatus built in
Bologna is one of the few existing in the world, and favoured
scientific collaborations with researchers of foreign Universities:
P.D. Burrow (University of Nebraska, Lincoln,m USA), K.D.
Jordan (UniversitÃƒ di Pittsburg, USA), H.D. Martin
(University of Dusseldorf), M. Tronc (University Pierre et Marie
Curie, Paris VI), A.P. Hitchcock (UniÃ‚Âversity McMaster,
Hamilton, Canada), J. Tamariz (University of Mexico City), L.
Szepes e L. Nyulaszi (University of Budapest), J.P. Schermann
(University of Paris 13, Villetaneuse), J. Nixon (University of
Sussex, Brighton), N.L. Asfandiarov (Academy os Sciences, Ufa,
We applied the above mentioned techniques to organic and
organometallic compounds (a survey is given in A. Modelli,
Trends in Chemical Physics (Research Trends) ,
6 (1997) 57-95).
X-ray photoelectron spectroscopy was used to determine
ionization energies from inner pseudo-atomic orbitals, and the
subsequent mechanisms of electronic relaxation and charge
re-distribution, mainly through shake-up processes, i.e., core
ionization accompanied by simultaneous excitation of a valence
electron to an empty orbital.
UV photoelectron spectroscopy was mainly applied to conjugated
p-systems and organometallic compounds to investigate on the
mechanisms of orbital interactions, nature of chemical bonds,
acceptor or donor properties of substituent functional groups,
Electron Transmission Spectroscopy (an electron-molecule
scattering technique) was employed to characterize (in energy and
localization properties) temporary anion states, following several
lines of research: systematic investigation on the acceptor
properties of hydrocarbons containing elements of the main groups
(14-17); metal-ligand interactions and charge distributions in
transitional complexes; frontier electronic structure in compounds
of environmental and biochemical interest. When the anion energy is
above the threshold for dissociation, the electron capture process
(resonance) may follow a dissociative channel (in kinetic
competition with simple detachment of the extra-electron). In this
case, a long-lived negative fragment and a neutral radical are
formed. DEA spectroscopy measures the yield of negative fragments
(with a mass filter), as a function of the electron impact energy.
In particular, we used DEAS to determine the efficiency of
intramolecular electron transfer between non-bonded functional
groups. A multidisciplinary approach, including all the above
mentioned techniques and theoretical calculations, was employed to
characterize the filled and empty level structures of organic
monomers and oligomers, extrapolating the results to the
corresponding conducting polymers.
Another field of research
is devoted to the determination of the extent and rate of
biodegradation of environmental pollutants. In particular, the ASTM
D 5988-96 method was used to study the biodegradability of various
polymeric materials and ionic liquids due to the action of
microorganisms present in the soil, in aerobic conditions.
The research activity led
to publication of about 170 papers on international