Fluorescence Spectroscopy Laboratory

This is Kenyon College's fluorescence spectroscopy laboratory obtained through a generous grant from the Howard Hughes Medical Institute .

The system consists of a HORIBA Jobin Yvon (SPEX) Fluoromax-3 fluorescence spectrophotometer with polarizers

Students in the Nanoscience and Materials Chemistry Lab (CHEM 126.04) obtain fluorescence spectra of CdSe quantum dots (QD), which they prepare. The fluorescence band maximum and hence color depends on the particle size of the QDs. Students explore this relationship using the particle-in-a-box model.

Students the Advanced Inorganic Chemistry Lab (CHEM 372) investigate the rate of energy transfer reactions between the excited-state metal complex *[Ru(bpy)3]2+ and aromatic energy acceptors such as anthracene and pyrene. Quantum yield (f) data obtained using the Fluorolog-3 spectrophotometer are compared to quenching data obtained using a laser lifetime system (NSF grant). Using a Stern-Volmer (SV) kinetics analysis, rate constants on the order of 109 M-1 s-1 are calculated, and the relationship between rate constants and thermodynamic driving force (DG) investigated.

Phosphorescence quenching of *[Ru(bpy)3]2+ (2.0 x 10-5 M) by pyrene having concentrations of: (1) 0 M, (2) 4.6 x 10-4 M, (3) 9.2 x 10-4 M, (4) 1.4 x 10-3 M, (5) 1.8 x 10-3 M,

Stern-Volmer plot of quenching data using from both luminescence intensity (quantum yield, f) measurements and lifetime (t) measuements. Student data show excellent agreement between the two methods.

Students in the Advanced Spectroscopy Lab (CHEM 374) also use this fluorescence spectroscopy facility.