Qualitatively explicate the difference in the stretching frequencies for F2, Cl2, Br2 and I2. Also define the difference in the stretching frequencies for N2, O2 and F2.
All are IR inactive.
F2 = 1365 cm-1, Cl2 = 789 cm-1, Br2 = 414 cm-1, I2 = 255 cm-1
N2 = 2744 cm-1, O2 = 2061 cm-1