this might or might not answer your question. One thing I know is that conjugation leads to more stable molecules, more stable molecules are lower in energy. No idea if this has anything to do with it but if you apply E=hf where E is the electromagnetic energy than E is directly related to frequency.
low E so low f? No idea. Something else I know relates to IR spectroscopy. How it works is that the molecules absorb electromagnetic radiation from IR photons. Which will then give us an absorbance spectrum. The absorbance has to do with vibrational energy of the molecule... higher vibration, more energy is absorbed and lower vibration less energy is absorbed. From my reference book, it shows that C triple bond has a higher absorbance then C double bonds.
