Fluorescence Lab Report Example | Topics and Well Written Essays - 500 words

Fluorescence - Lab Report Example In this experiment, anthracene was the electronically excited species while carbon tetrabromide was the quencher. A 250 ml solution of 0.1 mM anthracene (AN) was prepared in spectrometric quality n-hexane and used as a â€Å"solvent† to prepare 25 ml of 15 mM â€Å"stock† solution of CBr4. Eight dilutions of the AN/CBr4 were made using AN as the solvent starting with 0% (10 ml of AN) and ending with 100% (10 ml of CBr4). The solutions were then introduced into a fluorescence cell and deaerated with dry N2 for two minutes one after the other. The full fluorescence spectrum was then recorded using the instrumental conditions set by the TA. The fluorescent intensities of all the dilute solutions were recorded. The Stern-Volmer plot in this experiment is curved upward because the system is considered to be suddenly exposed to a steady-state excitation source. A graph of I0/I vs [Q] gives KÏ„0 as the slope. The rate constant value obtained from the Stern-Volmer plot was 8393.7 Lmol-1s-1 while the theoretical value is estimated at 5.37 Ãâ€" 10^10 Lmol-1s-1. The rate constant obtained in this experiment is lower than the theoretical value due to factors such as ground-state complex formation between A and Q, competition between A and Q for the incident light and polarization effects. From equation 10 a graph of (I0/I) versus [Q] gives KqÏ„0 as the slope, and knowing the numerical value of Ï„0 then the value of Kq can be