A simple molecular dynamics experiment is described to demonstrate transport properties for the undergraduate physical chemistry laboratory. The AMBER package is used to monitor selfdiffusion in n-hexane. Scripts (available in the Supporting Information) make the process considerably easier for students, allowing them to focus on the simulations and their meaning. Meansquared displacements are determined as a function of simulation time for 250 ps in a small simulation box at a variety of temperatures. From these, the Einstein−Smoluchowski and Stokes−Einstein relationships are used to determine the viscosity, which can be directly compared to literature values. The needed trajectories can be calculated in less than 1 h and analyzed in a second hour, leaving a third hour for further explorations as appropriate.

The photocatalytic degradation of the X-ray contrast agents iohexol and diatrizoate are monitored by in situ Raman spectrometry measurements in aqueous solution with a TiO 2 photocatalyst. Spectral features and changes are interpreted with the use of density functional theory calculations. While we observe similar results to those published previously, significant changes seen in the Raman spectrum allow us to better identify the mechanisms without the need for deductive approaches or complicated sample preparation. Diatrizoate spectra are consistent with hydroxyl radical attack leading to the loss of CO 2 . Iohexol is more difficult to interpret, representing a current challenge to the use of Raman spectrometry for real-time monitoring of photocatalytic degradation experiments. We explore internal standards that can be added to gauge overall degradation rates to some extent. Potential extensions of the work are described, particularly in terms of increased rate of data acquisition and more general application.

Temperature-dependent infrared spectra of aqueous nitrate solutions with a range of concentrations and ionic strengths are used to determine the effect of ionic strength on the relative stabilities of different solvation geometries in aqueous nitrate ion. The asymmetric stretching absorption band from 1250 to 1450 cm changes line shape with temperature, allowing two distinct peaks to be fit for each spectrum. Because each peak is assigned based on electronic structure calculations as a proxy to a different solvation motif, van't Hoff plots provide insight into the thermodynamics of exchange between different solvation geometries. A strong linear trend is seen between increased ionic strength and the magnitude of both the enthalpic and entropic contributions to the solvation geometry stabilities. Electronic structure computations of previously proposed structures in different ionic strengths are performed in the presence of external fields, roughly simulating the impact of ions in solution.