Similarly, the UV/vis absorption spectra of caffeine in dichloromethane was found to be in the region of 243–301 nm. Its peak absorbance A = 1.043 was obtained at maximum wavelength View the MathML source. The molar decadic absorption coefficient of caffeine in dichloromethane View the MathML source is obtained. Fig. 3 shows the peak absorbance versus maximum wavelength of caffeine in dichloromethane. And Fig. 4 below shows the graph of View the MathML source versus View the MathML source in dichloromethane. The integrated area under this graph is IA = 114.16 m2 mol−1 in the wave number between View the MathML source and View the MathML source. From the integral absorption value the transitional dipole moment of caffeine in dichloromethane is determined to be μfi = 10.80 × 10−30 C m.