This Research at Undergraduate Institutions (RUI) project extends upon successful past laboratory studies conducted by the P.I. investigating thermodynamic properties of aqueous and mixed-solute systems that emulate aerosol particles resident in the upper troposphere. Laboratory experiments will expand the range of thermochemical data - including equilibrium phase diagrams and solution heat capacities as a function of temperature and chemical composition - on a number of tropospherically relevant aqueous systems, using differential scanning calorimetry (DSC) and infrared (IR) spectroscopy. The P.I. will also verify theoretical model thermodynamics at low temperature by measuring enthalpies of fusion and solid-solid phase transitions of these systems, enabling identification of unknown solids in mixtures of several components at cold temperatures in the future. Undergraduate students will be extensively involved in laboratory experimental work and data analysis. With respect to broader impacts, this project will make a substantive contribution to current understanding of some important aerosol systems present in the global troposphere that influence radiative balance and cloud nucleation, while enhancing the education, professional training and research experience of a number of undergraduate students at a relatively small tertiary institution. The project results will provide the atmospheric science community with new data that may lead to more realistic and representative constraints on existing aerosol thermodynamic models.
