Question

Vibrational frequency (cm-1) of -C= N-

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Answer 1

Answer:  Although the harmonic oscillator proves useful at lower energy levels, like n=1, it fails at higher numbers of n, failing not only to properly model atomic bonds and dissociations, but also unable to match spectra showing additional lines than is accounted for in the harmonic oscillator model.

Anharmonicity

Until this point, we have been using the harmonic oscillator to describe the internuclear potential energy of the vibrational motion. Fundamental vibrational frequencies of a molecule corresponds to transition from Δv=±1. While this is a decent approximation, bonds do not behave like they do in the Harmonic Oscillator approximation (Figure 13.5.1). For exaple, unlike the parabola given in the Harmonic Oscillator approximation, atoms that are too far apart will dissociate

Explanation: