This lab provides instructions for the synthesis of nanoscale silver colloidal particles along with questions to guide student thinking regarding the molecular-scale interactions between acids, bases, salts and sugar with the silver particles.
A UV-Vis spectrophotometer (300-800 nm) is used to record the spectrum as electrolyte solution is slowly added over time. The interesting optical scattering effect of the nanoscale particles is also investigated.
The Nanosphere Optics Lab simulation tool is then used to calculate the scattering expected from specific nanosized silver particles according to Mie theory, using computational electrodynamics calculations. Discussion questions lead students to trends between the extinction maximum, the particle size and the refractive index of the solution, and towards matching simulation results with their experimentally obtained spectra.
This is a purely computational project that is concerned with using the nanoHUB tool QC-Lab to create and optimize molecules, and to study their spectroscopic and structural properties. The molecules studied are generally small molecules of interest to atmospheric chemistry, however the tool can be used for applications in nanoscience, and there are followup projects (not appropriate for freshman) that study the properties of carbon nanotubes and molecules important in vision.