By Sunil Bhardwaj


(a) Diatomic molecules with simple harmonic oscillator fails to explain the higher vibrational states. Thus it requires correction.

(b) In harmonic oscillators, the vibrational energy levels go on decreasing, according to experimental results observed. But they are represented by equal spacing.

(c) Over-tones and combination terms are also observed in vibrational spectra. But the harmonic oscillator does not explain this fact. Hence, it is necessary that the diatomic molecules should be considered as anharmonic oscillator.