Profiles

Professor P W Fowler

Office: G9
Telephone: (0) 114 22 29538

Professor: BSc University of Sheffield (1977); PhD University of Sheffield (1980); SERC Postdoctoral Fellow University of Cambridge (1980-83); Senior Demonstrator University of Durham (1984-85); Postdoctoral Research, University of Cambridge (1985); Lecturer in Physical Chemistry (1985-1990) Reader in Theoretical Chemistry (1990-1995) and Professor (1995-2005) of Theoretical Chemistry, University of Exeter. Professor of Chemistry, University of Sheffield (2005-present).

Awards

RSC Corday-Morgan Medal (1992); RSC Tilden Lecturer (2004/5); Professeur Invité, Ecole Nationale Supérieure, Paris (1996-2005); Royal-Society-Wolfson Research Merit Award (2004-2009); Professeur Invité, Université Paul Sabatier, Toulouse (2007).

Keywords

Theoretical chemistry, molecular properties, ring currents, aromaticity, fullerenes, molecular electronic devices, symmetry and discrete mathematics in chemistry.

Research Interests

Aromaticity: Attribution of aromaticity to a molecule is associated with a loose cluster of criteria based on geometric, energetic and reactivity properties, but one persuasive definition is based on magnetic properties: ability to sustain an induced diatropic ring current. Using modern ipsocentric methods it is possible to perform calculations that map the currents, giving a direct quantitative visualisation of aromaticity and anti-aromaticity, but also explaining the patterns of current in terms of orbitals, energies, nodes and symmetry the standard toolkit of qualitative chemical theory. Our most recent work includes a qualitative `band theory´ of the currents in giant graphite-flake molecules. Two new projects investigate the magnetic response of `exotic carbon nanostructures´, including toroidal and Möbius-twisted carbon (PhD research project of David Bean) and the connection between induced currents and the ballistic currents in single-molecule devices (PhD research project of Tsanka Todorova). We are working on ring-current aspects of the many proposed types of aromaticity, aiming to supply symmetry/topological criteria for each. We have strong collaborations in this area with Physical Organic and Theoretical Chemistry groups in Utrecht, Warsaw, Modena, Salerno and Toulouse.

Fullerenes: We are exploring the systematic theoretical chemistry of the fullerenes based on classical chemical ideas e.g. the 60+6k `leapfrog principle´ equivalent of Hückel´s 4n+2 rule. A series of papers and a book, the `Atlas of Fullerenes´ (OUP, now in Dover), have contributed to a comprehensive qualitative theory of the fullerenes using graphs, groups, and discrete mathematics to derive principles for enumeration, geometry, electronic structure, spectroscopic signature, isomerisation, growth & destruction, and reactivity. Rationalisation of stoichiometry, structure, symmetry of species such as fully brominated C₆₀Br₂₄ by purely combinatoric arguments led to our ongoing investigation of `closed-shell independence numbers´. We are collaborating on graph-theoretical aspects of fullerenes with Mathematics and Computer Science groups at the Universities of Ghent, Malta and Victoria (BC).

Molecular properties: Two areas of longstanding interest are the properties of weak complexes, modelled using electrostatic and other considerations from the theory of intermolecular forces, and the properties of ions in crystals, where the focus is on computation of the drastic effects of the crystalline environment on electric properties especially of anions, and the interpretation of these changes in terms of electrostatic and overlap models.

Interdisciplinary: Group theory as used by chemists has applications in many neighbouring fields. Symmetry generalisations of engineering principles such as Maxwell´s Rule and Mobility Criteria, symmetry aspects of mathematical theorems such as the Euler Theorem, and symmetry in packing and covering problems are being investigated with research collaborators in Cambridge, Leuven and Budapest.

Selected Publications

A. Soncini, P.W. Fowler: Ring-current aromaticity in open-shell systems, Chem. Phys. Lett. 450 (2008) 431-436
R.W.A. Havenith, P.W. Fowler: Ipsocentric Ring Currents in Density Functional Theory, Chem. Phys. Lett. 448 (2007) 75-82.
E. Steiner, P.W. Fowler, A. Soncini and L.W. Jenneskens, Faraday Discussions 135 (2007) 309-323. Current-density maps as probes of aromaticity: Global and Clar π ring currents in totally resonant polycyclic aromatic hydrocarbons.
G. Monaco, P. W. Fowler, M. Lillington and R. Zanasi, Angewandte Chemie International Edition 46 (2007) 1889-1892. Designing paramagnetic circulenes.
M. K. Cyrański, R.W.A. Havenith, M.A. Dobrowolski, B.R. Gray, T.M. Krygowski, P. W. Fowler and L.W. Jenneskens, Chemistry A European Journal 13 (2007) 2201-2207. The Phenalenyl Motif: a Magnetic Chameleon.
P.W. Fowler and B.R. Gray, Inorganic Chemistry 46 (2007) 2892-2897. Induced currents and electron counting in aromatic boron wheels B₈^2- & B_9-.
R.W.A. Havenith and P.W. Fowler, PCCP 8 (2006) 3383-3386. The origin of the ring current in the all-metal aromatic Al₄^2-.
P.W. Fowler, A. Rogowska, A. Soncini, M. Lillington and L.P. Olson, J. Org. Chem. 71 (2006) 6459-6467. Currents in tangentially p-p bonded σ-aromatic systems.
A. Soncini, C. Domene, J.J. Engelberts, P.W. Fowler, A. Rassat, J.H. van Lenthe, R.W.A. Havenith and L.W. Jenneskens, Chemistry A European Journal, 11 (2005) 1257-1266. A unified orbital model of delocalised and localised currents in monocycles, from annulenes to azabora-heterocycles.
P.W. Fowler C.W. Rees and A. Soncini, J. Am. Chem. Soc., 126 (2004) 11202-11212. Aromaticity of organic heterocyclothiazenes and analogues.
P. W. Fowler and E. Steiner, Chem. Phys. Lett. 364 Pseudo-π currents: rapid and accurate visualisation of ring currents in conjugated hydrocarbons (2002) 259-266
E. Steiner and P.W. Fowler, Chem. Comm. (2001) 2220-2221 Four- and two-electron rules for diatropic and paratropic ring currents in monocyclic π systems
E. Steiner and P.W. Fowler, J. Phys. Chem. 105 (2001) 9553-9562 Patterns of ring currents in conjugated molecules: A few-electron model based on orbital contributions.
P.W. Fowler, R.W.A. Havenith and E. Steiner, Chem. Phys. Lett. 342 (2001) 85-90 Unconventional ring currents in an all-metal aromatic, Al₄^2-.
E. Steiner, P.W. Fowler and L.W. Jenneskens Angew. Chemie Int. Edn., 40 (2001) 362-366 Counter-rotating ring currents in coronene and corannulene.
P.W. Fowler, S. Daugherty and W. Myrvold, Independence Number and Fullerene Stability, Chem. Phys. Lett. 448 (2007) 75-82.
P.W. Fowler, D. Horspool and W. Myrvold, Chemistry A European Journal 13 (2007) 2208-2217. Vertex spirals in fullerenes and their implications for nomenclature of fullerene derivatives.
P.W. Fowler and I. Sciriha, Nonbonding Orbitals in Fullerenes: Nuts and Cores in Singular Polyhedral Graphs, J. Chem. Inf. Mod. 47 (2007) 1763-1775.
J.-P. Malrieu, C. Lepetit, M. Gicquel, J.-L. Heully, P.W. Fowler, R. Chauvin: Evaluating the cyclic π-electron delocalization energy through a double cut of conjugated rings, New J. Chem. 31 (2007) 1918-1927.
S.D. Guest and P.W. Fowler, Journal of Mechanics of Materials and Structures, 2 (2007) 293-301. Symmetry conditions and finite mechanisms.
T. Tarnai and P.W. Fowler, Proc. Roy. Soc. A, 462 (2006) 3733-3747. Packing of twinned circles on a sphere.
F. Kovács, T. Tarnai, S.D. Guest and P.W. Fowler, Proc. Roy. Soc. A, 460 (2004) 3191-3202. Double-link expandohedra: a mechanical model for expansion of a virus.
P.W. Fowler and D.E. Manolopoulos, An atlas of fullerenes, Dover Publications (2006) ISBN 0-486-45362-6, Oxford University Press, (1995) ISBN 0-19-855787-6.