Singapore Millennium Foundation Fellow, National University of Singapore, 2002-2004; Postdoc. Research Associate, University of Cambridge, 1996-2002; Ph. D., University of Cambridge, 1997; M. A., University of Cambridge, 1996; B. A., University of Cambridge, 1992.
Contact Information:
Office: MD1-17-03J
Tel: (65)-6516-5130
Fax: (65)-6779-1691
Email: chmaml@nus.edu.sg
NASA Achievement Award, NASA, 1996
Atmospheric Science and Computational Chemistry
The bulk of my research involves the use of numerical models to study the present state of the atmosphere and its evolution. Of particular concern is the evolution of ozone in the atmosphere.
In the stratosphere, ozone acts as a shield preventing potentially lethal ultraviolet radiation reaching the biosphere. In this region of the atmosphere, ozone has been declining and my research in this area has focused on understanding the development and future evolution of the Antarctic Ozone Hole. A significant result of my research has been to establish the fact that climate change induced by greenhouse gases will delay the future recovery of the ozone hole despite the expected decline in halocarbons following the implementation of the Montreal Protocol.
In the troposphere, ozone is the most irritant of the common air pollutants and exposure to large concentrations causes inflammation of the respiratory tract and morphological changes in the lung. Studies indicate that monthly-averaged ozone concentrations will exceed 130 parts per billion over large parts of Southeast Asia towards the end of the century well in excess of recommended thresholds to exposure. My research has attempted to assess the environmental impact and economic cost of the present behaviour and the future evolution of tropospheric ozone and other greenhouse gases. The strategy has been to couple a two-dimensional chemistry-climate model to an environmental macroeconomic model. This model is being used to identify long-term abatement strategies at minimum economic cost.
On a more theoretical level, I am also interested in calculating, from first principals, rate coefficients for some of the more important atmospherically significant reactions.
Ref: Bettens, R. P. A.; Lee, A. M. On the accurate reproduction of ab initio interaction energies between an enzyme and substrate. Chem. Phys. Lett. 2007, 449, 341-346.
This study reports the fragmentation of an entire enzyme and substrate and shows that the majority of the small fragment molecule interactions can be accurately evaluated without the need to compute the ab initio interaction energy. The perturbation approach presented in this work indicates the possibility to perform accurate first principles molecular dynamics in systems as large as proteins. The −0.018 a.u. isosurface of the electrostatic potential for the influenza neuraminidase tetramer computed from first principles via energy-based molecular fragmentation. This isosurface reveals that the most energetically favorable approach of an anion to the tetramer is only along a path that leads to a region of the enzyme that includes the active site and secondary binding site for sialic acid.
