Current Activities
Our research program is primarily focused on four areas:
(i) Complete vibrational morphed potentials optimized for non-covalent molecular interactions. Non-covalent molecular interactions are ubiquitous throughout nature. Such interactions are important for their influence on the properties of gases, liquids and solids from a small molecule such as hydrogen bromide to intricate dynamics associated with DNA and protein folding. It has become apparent that the generation of molecular based potential energy surfaces capable of characterizing and reliably predicting the properties of prototypical interactions can make significant contributions to a range of such phenomena. In collaboration with Dr. R. R. Lucchese, we initiated generation of morphed potentials in van der Waals complexes, Rg:Hx (R=Ne, Ar, Kr; X=Br, I) based on transformation of ab-initio potential energy surfaces to accurately reproduce their high resolution spectroscopic data. We are now especially interested in exploring the application of such methodologies to hydrogen bonded interactions with higher dimensionality and with concurrent spectroscopic investigations so that procedures can be developed for more general application of morphed potentials.
(ii) Development of spectroscopic instrumentation and techniques. As an adjunct to our spectroscopic investigations, we custom construct spectroscopic instrumentation and related techniques. We have recently designed a multi-purpose frequency and phase stabilized submillimeter backward wave oscillator spectrometer. Currently, static gas phase sub-Doppler spectroscopy can be used to provide linewidths of < 16 kHz (5x10-7 cm-1) with precision of up to 15 Hz (5x10-10 cm-1). A sensitive co-axially configured supersonic jet version of this instrument has recently been completed with a linewidth <20 kHz and an accuracy of <1 kHz for molecular studies at less than 10 Kelvin. The spectrometer is being upgraded for investigations in molecular interactions of significance in biological chemistry, pollution monitoring and reaction dynamics ?in the Terahertz gap? 4.0 to 43 cm-1, and higher.
(iii) Environmentally compatible non-thermal surface wave plasma-based technologies for hazardous waste disposal. Since our group initiated the application of surface wave plasma (SWP) abatement for environmental purposes, we have been repeatedly surprised at its versatility for pollution mitigation. The unique properties of this traveling-wave plasma technology have been demonstrated to be particularly effective for destruction and removal (DRE) of PFCs and HFCs emitted into the atmosphere during 200 mm semiconductor manufacture. We are now focusing on fundamental investigations for modeling alpha and beta tests for 300 mm semiconductor process technologies and DRE of ozone-depleting CFCs. Our recently developed capability of studying electron-molecule collisions with pico-eV final state spectroscopic resolution is thought to have important advantages for such investigations.
(iv) State-specific molecular screening of diseases. State-specific molecular monitoring provides a unique and rapid approach to medical diagnostics. We are currently developing new analytical techniques and procedures based on such approaches that effectively constitute a breathalyzer for screening and diagnosis of lung cancer and other diseases. Our point-of-test non-invasive approaches involve both laboratory and pre-clinical investigation.
Selected Publications
B.A.McElmurry, S.P. Belov, R.R. Lucchese, and J.W. Bevan, " Analysis of the Submillimeter Ar:HI Σ Bending Transition as a Test of a Morphed Potential ", Phys. Chem. Chem. Phys. 6, 5318-5323 (2004). R.R. Lucchese, J.W. Bevan, and F.J.Lovas, " Microwave Spectra of Ne:HBr: Structural Perspectives on Rg:HX, Rg = Ne, Ar, Kr; X = F, Cl, Br, I", Chem. Phys. Letts. 398, 544-552 (2004). A. L. McIntosh, Z. Wang, R.R. Lucchese, and J.W. Bevan, "High Frequency Wavelength Modulation CW Slit Jet Diode Laser Spectrometer for Characterizing Ground State Intermolecular Hydrogen Bonded Vibrations", Infrared Phys. and Tech. 45 (4) 301-314 (2004) J. Castillo-Chara, A. L. McIntosh, Z. Wang, R.R. Lucchese, and J.W. Bevan, "Near Infrared Spectra and Ro-Vibrational Dynamics on a Four-Dimensional Ab-Initio Potential Energy Surface of (HBr) 2 ", J. Chem. Phys.120, 10426-10441 (2004) Z. Wang, R.R. Lucchese, and J.W. Bevan, "A Kr-BrH Global Minimum Structure Based on Potential Morphing", J. Phys. Chem. 108A, 2884-2892 (2004) B.A. McElmurry, R.R. Lucchese, J.W. Bevan, I.I. Leonov, S.P. Belov and A.C. Legon "Studies of Ar:HBr Using Fast Scan Submillimeter-wave and Microwave Coaxial Pulsed Jet Spectrometers", J. Chem. Phys. 119 (20): 10687-10695 (2003) J. Castillo-Chara, John W. Bevan, Robert R. Lucchese, "Fitting of an ab initio potential of two linear-rigid-rotor-dimer and the calculation of rovibrational energy levels by the pseudo-spectral approach" Computer Physics Communications 145, 48-163 (2002). A.L. McIntosh, B.A. Wofford, R.R. Lucchese, and J.W. Bevan, "High resolution Fourier transform infrared spectroscopy using a high temperature argon arc source," Infrared Phys Techn 42 (6): 509-514 (2001). B.A. Wofford and J.W. Bevan, "Current Status of Surface Wave Plasma abatement of Semiconductor Global Warming Emissions," Fut. Fab. International 11, 89-96 (2001). J Castillo-Chara, R.R. Lucchese, J.W. Bevan, "Differentiation of the ground vibrational and global minimum structures in the Ar : HBr intermolecular complex," J Chem Phys 115 (2) 899-911 (2001). C. Hartz, B.A. Wofford, M. Jackson, and J.W. Bevan, "Surface Wave Plasma Abatement of CHF3 and CF4 Containing Semiconductor Emissions," Environ. Science and Technology, 34, 1892-1897, (1999).
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