Fluorescence Lab

Introduction Fluorescence is a type of photoluminescence spectroscopy. Fluorescence occurs when a photon is emitted from a molecule as it moves from a higher excited state to a lower excited state with in the same spin. A molecule normally is in its ground state energy. When a light source puts off an electromagnetic energy, the molecule can move to a higher more excited energy. When the molecule transitions down in energy, it usually is released as heat. Conversely, if the molecule is subject to high energy the molecule can transition down to its ground state by fluorescence. This emission of a photon creates wavelengths that are captured by spectrophotometric methods. Fluorescent intensity is represented by the equation F=k C. Where F is
The completed calculations can be found on lab notebook page 14. Using this data, graph 2 was generated showing the relationship between the intensity ratio and the concentration of chlorine. Relating to the Stern-Volmer equation of F0/F=1+KSV[Q] and the linear line equation of y = 124x + 1.08, the KSV is the slope of the equation 124. Compared to the literature value of KSV of 184, the relative error as a percent was calculated to be 32.6% [2]. This was calculated by finding the difference between the measure value and the literature value, divided by the literature value then multiplied by 100. The completed calculation can be found on lab notebook page 15. Heavy atoms in the solution promote intersystem crossing. Intersystem crossing is when a molecule has been excited and resides into the lowest vibrational energy level of a high transitional energy state, and then transitions to a high vibrational energy level of a lower transitional energy and does not produce a photon. This is occurs often when heavy halides are in the solution because they increase vibrational relaxation
We also learned from our results the significance that halides had on the quenching of fluorescence intensity of quinine. When chlorine was present in the quinine solution, the fluorescence intensity decreased. As well as the more concentration of chlorine, the more quenching that occurred. The halide prevents the emission of a photon, fluorescence, and the heavier the atom the more quenching that occurs. The significance of the sample matrix was also learned based on our results. It was determined that the matrix’s ability to absorb energy from a light source based on its color, affected it’s ability to emit a photon and produce fluorescence intensity. Lastly, the significance of the voltage on the amount of fluorescence intensity was studied. From the equation F = k C, it was understood that increasing the voltage increases the