IR laser spectroscopy of molecular structures & dynamics of bio-mimetics, & dynamics of bio-mimetics, & spectroscopic studies of large-amplitude motions in molecules of astrochemical & atmospheric imp

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One of the fascinating current questions in molecular and biological physical chemistry is the mechanism of protein folding. What are the energetics and the dynamics of the motions of these large biomolecules? To seek insights, we will undertake high-resolution spectroscopic study of biomimetics at UNB and the FIR beamline at the CLS synchrotron in Saskatoon. Biomimetics are medium-sized molecules which mimic the structures and internal motions of subunits of larger biomolecules, providing windows into the folding behaviour and torsional flexibility of the larger parents. We will study the weak torsional fundamentals at the CLS taking advantage of the bright synchrotron source, and we will probe bending and stretching vibrations of the heavy-atom molecular backbones in-house at UNB to exploit these modes as "doorway" states to couple to and give information about the torsion. Using complementary experimental and ab-initio approaches, we aim to explore (i) the number, shape and energy of different molecular conformations, (ii) barriers to folding, and (iii) tunneling pathways, features all directly related to the folding structures in peptide chains. Our second area of research deals with the complex interactions between vibrations and torsion in smaller molecules such as methanol. Here, we are analyzing the IR absorption bands in order to understand and model the energy structure and intermode coupling, and to provide information to a wide audience of atmospheric and space scientists. Recent observations of methanol in forest fires, the atmosphere and comets have generated a strong demand for database information. Astronomically, methanol is now identified as the worst interstellar "weed" with an abundance of strong lines throughout the entire spectrum that interfere with other molecules of interest. A collaboration with the NASA Jet Propulsion Lab on compilation of position and intensity data will fill an important gap in the next version of HITRAN, the international atmospheric database. To further advance the frontiers, we will initiate multi-state global modeling for much improved accuracy and capability for reliable simulation of methanol absorption bands over a wide range of atmospheric and astrochemical conditions.