P age |6
Speed of light(c)=3 x 108 ms-1
Dye Solution
𝜆1 (in nm)
𝜆2 (in nm)
Stokes Shift
1
1
(∆𝐸 = hc ( – ))
𝜆1 λ2
(eV)
Rhodamine 6G
532
553
0.0042
Coumarin 480
Quinine Sulphate
392
333
470
364
0.525
0.327
Note: 1eV =1.602x10-19J
Figure 5: Stokes shift in the Double Y plot of absorbance and emission for respective dyes
INFERENCE
Fluorescence Quantum Yield values range between 0 and 1 ideally. A higher value of QY
corresponds to stronger fluorescent intensities. From the graphs plotted using data
obtained and the calculations with respect to the Rhodamine 6G reference standard,
Quantum Yield of Coumarin 480 and Quinine Sulphate is obtained as 1.27 and 0.0966
respectively. Thus, Coumarin 480 is a strong fluorophore.