What is the value of :13}, if the value of 25., is 2988.9 cm\". Consider calculating AG(v). Harmonic vs. Anharmonic Oscillators To determine the anharmonicity of the bonds in H35Cl. a spectroscopist measures the fundamental and overtone absorption bands at 2885.7, 5668.2, and 8347.5 cm-1. The equation that describes energy levels of an anharomnic oscillator is given by G(v) = We(v + 1/2) - Tewe(v + 1/2)2