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 kmax ¼ 274:7 nm. The molar decadic absorption coefficient of caffeine in dichloromethane
emax ¼ 1010 m2 mol1 is obtained. Fig. 3 shows the peak
absorbance versus maximum wavelength of caffeine in
dichloromethane. And Fig. 4 below shows the graph of
eðmÞ=~m versus ~m in dichloromethane. The integrated area
under this graph is IA = 114.16 m2 mol1 in the wave number
between ~m1 ¼ 33; 000 cm1 and ~m2 ¼ 41; 000 cm1.
From the integral absorption value the transitional dipole
moment of caffeine in dichloromethane is determined to
be lfi = 10.80 1030 C m.
3.2.