For a diatomic molecule, the maximum vibrational energy that a molecule can have prior to its @D01547@ into the ground electronic states of the @C01281@ atoms (spectroscopic @B00699@, \(D_{\text{e}}\)). The \(D_{\text{e}}\) value is related to the chemical @D01801@ energy: \(D_{\text{0}}=D_{\text{e}}- \mathrm{E}_{\text{vib}}\left(0\right)\), where \(\mathrm{E}_{\text{vib}}\left(0\right)\) is zero-point vibrational energy. This definition is usually extended to the @D01801@ of polyatomic molecules into certain molecular fragments through homolytic or heterolytic bond cleavages.