CAREER: Reaction dynamics study of biomolecular ions with electronically excited singlet molecular oxygen using guided-ion-beam scattering and direct dynamics trajectory methods

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In this project supported by the Chemical Structure, Dynamics, and Mechanisms Program of the Division of Chemistry, Professor Jianbo Liu and his research group at the Queens College of the City University of New York will study the reaction of biomolecules such as amino acids and dipeptides with a reactive oxygen species called singlet molecular oxygen (^1 O2). Singlet O2 is generated in nature from normal oxygen molecules in the presence of visible/ultraviolet light from the sun. The reaction of biomolecules with singlet O2 is not only interesting from the standpoint of chemical reaction dynamics, but is also an important topic because of connections to biological processes such as aging and diseases (e.g. cataracts and some skin cancers), as well as photodynamic therapy for cancer and photochemical transformations of biological species in the atmosphere and oceans. Professor Liu and his team will conduct a systematic study of the reaction of biomolecules with singlet O2, aimed at achieving a molecular level understanding of the reaction mechanism and reaction kinetics/dynamics. The experimental systems range from isolated biomolecules in the gas phase in the absence of water, through gas-phase hydrated biomolecules with a few water molecules attached, to biomolecules in liquid water. The experimental techniques employed include guided-ion-beam scattering and electrospray ionization mass spectrometry. Since the photosensitization method for producing singlet O2 often produces ozone and other undesirable species that complicate the results, Professor Liu's laboratory will employ a chemical technique to generate pure singlet O2 for reactions with biomolecules. The experimental work will be complemented by theoretical calculations, including ab initio electronic structure calculations and direct dynamics trajectory simulations.Professor Liu's research program will train not only graduate and senior undergraduate students at CUNY, but will also involve high school students through his participation in the Queensborough Bridge Program and MARC-U*STAR Program, which engage community college students and minority students in science. Also, in coordination with the CUNY pre-college summer research program, students from local high schools will work in the Liu laboratory, and their results will be translated into competitive science fair research projects. This research program is also integrated into Professor Liu's formal course teaching. He will use his research equipment to develop new experiments (e.g., simulations of ion trajectories, and collision-induced dissociation of molecules) in Physical Chemistry and Instrumental Analysis Laboratories.