Associate Professor Ryan P A BETTENS

B.Sc., 1986, University of Queensland; Ph. D., 1992, Monash University; Postdoctoral Res. 1992-1994 ETH; Postdoctoral Res. 1994-1996 Ohio State University; Postdoctoral Fellow 1996-1998 RSC, Australian National University; Research Fellow 1998 - 2000 RSC, Australian National University

Contact Information

Department of Chemistry, NUS 
3 Science Drive 3 
Singapore 117543 
Office: MD1-05-03C
Tel: (65)-6516-2846 
Fax: (65)-6779-1691

Research Interests

Physical Chemistry/Chemical Physics

My research interests encompass a broad range of topics in physical chemistry: high resolution spectroscopy, the modelling of large-scale complex chemical reactions and computational chemistry. The high resolution spectroscopic technique I am mostly interested in is microwave spectroscopy. Microwave spectroscopy is an experimental spectroscopic technique used to measure the pure rotational and vibration-rotational (rovibrational) spectra of gas-phase species. Assignment, analysis and interpretation of a spectrum yields accurate structural and sometimes detailed dynamical information about a molecule or complex. Very recently a 75 - 110 GHz spectrometer was constructed and commissioned in my laboratory, and we are currently measuring and assigning the spectra of several significant biomolecules and molecules of interest to radio astronomers and interstellar chemists.

The reaction systems studied in my group include interstellar chemical systems, the Maillard reaction, and the chemistry of antioxidants. Interstellar chemistry is the study of the chemistry of molecules in space. My work in this area focuses largely on the gas-phase synthesis of molecules observed with radio telescopes. I develop large-scale gas-phase chemical kinetic computer models that are utilised in order to predict the observed abundances of interstellar species. These models involve thousands of bimolecular and unimolecular reactions and hundreds of highly unusual molecules by Earth standards. This aspect of my research program is purely theoretical, and involves a wide range of fields some of which are: kinetics, thermodynamics, computational chemistry and photochemistry. My work on the Maillard reaction and the chemistry of antioxidants is done in collaboration with Dr Leong Lai Peng from Food Science and Technology here at the NUS. My contribution to the collaboration is largely theoretical involving computer chemical kinetic modelling and ab initio calculations relevant to the various reactants, products and transition states involved in the mechanisms.

On the purely computational chemistry side, I am interested in calculating, from first principals, accurate fundamental frequencies of molecules and complexes. The first principal calculation of rovibrational spectra of molecules containing up to ten atoms and beyond is the ultimate goal. At present, such calculations have only been possible for triatomics, and simplified tetra atomics. A new method developed here, which is an amalgamation of several theoretical techniques, makes the above mentioned "first principal" calculations possible. Work is currently in progress on well understood triatomic systems - as a test of the new method - and tetra atomic systems.

Representative Publications

  • H.-A. Le, H.-J. Tan, J. F. Ouyang and R. P. A. Bettens*.  Combined Fragmentation Method: A Simple Method for Fragmentation of Large Molecules.  J. Chem. Theory & Comput., 8, 469-478 (2012)
  • M. Y. Patuwo and R. P. A. Bettens*. Monte Carlo Simulation of Several Biologically Relevant Molecules and Zwitterions in Water.  Chem. Phys. Lett., 524, 90-95 (2012).
  • H.-A. Le, A. M. Lee and R. P. A. Bettens*.  Distributed Multipoles and Energies of Flexible Molecules.  J. Chem. Theory & Comput., 7, 921-930 (2011)
  • H.-A. Le, A. M. Lee and R. P. A. Bettens*.  Accurately Reproducing Ab Initio Electrostatic Potentials with Multipoles and Fragmentation.  J. Phys. Chem. A, 113, 10527-10533 (2009)
  • R. P. A. Bettens* and A. M. Lee.  On the Accurate Reproduction of Ab Initio Interaction Energies Between an Enzyme and Substrate.  Chem. Phys. Lett., 449, 341-346 (2007)
  • A. M. Lee and R. P. A. Bettens*.  First Principles NMR Calculations by Fragmentation.  J. Phys. Chem. A, 111, 5111-5115 (2007)
  • R. P. A. Bettens* and A. M. Lee.  A New Algorithm for Molecular Fragmentation in Quantum Chemical Calculations.  J. Phys. Chem. A, 110, 8777-8785 (2006)
  • R. P. A. Bettens*.  Bound State Potential Energy Surface Construction: Ab Initio Zero-Point Energies and Vibrationally Averaged Rotational Constants.  J. Am. Chem. Soc., 125, 594-587 (2003)
  • R. P. A. Bettens. Bound State Potential Energy Surface Construction: Ab initio Zero-point Energies and Vibrationally Averaged Rotational Constants. J. Am. Chem. Soc., in press (2003).
  • R. P. A. Bettens and M. A. Collins. Multiple Surface Long Range Interaction Potentials Between C (3Pj) and Closed Shell Molecules. J. Chem. Phys.116, 101 - 104 (2002).
  • R. P. A. Bettens and M. A. Collins. Capture Rates for Collisions of C (3Pj) and Ge (1S0) with Unsaturated Hydrocarbons. J. Chem. Phys.114, 10342 - 10354 (2001).
  • F. L. Bettens, R. P. A. Bettens, R. D. Brown and P. D. Godfrey. The Microwave Spectrum, Structure, and Ring-puckering of the Cyclic Dipeptide Diketopiperazine. J. Am. Chem. Soc., 122, 5856-5860 (2000).
  • T. J. Millar, E. Herbst and R. P. A. Bettens. Large Molecules in the Envelope Surrounding IRC+10216. Mon. Not. R. Astron. Soc.316, 195-203 (2000). 
  • D. T. Petkie, T. M. Goyette, R. P. A. Bettens, S. P. Belov, S. Albert, P. Helminger and F. C. DeLucia. A Fast Scan Submillimeter Spectroscopic Technique. Rev. Sci. Instr.68, 1675-1683 (1997).