An Alternative Interpretation of the Covalent Bond
My last post her related to the use of quantum mechanics in chemistry, and it was intended as a prelude to a post about the ebook I had written and was editing. As you may see from looking at the dates, this has taken somewhat longer than I expected. This book outlines a methodology by which, ignoring minor effects, the chemical bond length and energy for covalent bonds involving only s and p electrons can be calculated often within less that 1% error solely by means of wave properties, the quantization of action, and the electric field coupling at the wave antinode. The only inputs are quantum numbers, the Exclusion Principle, and the number of electrons, hence simple analytical functions are obtained. The procedure uses atomic orbitals that do not correspond to the excited states of hydrogen, and this leads to a previously unrecognised quantum effect, and then counts the number of interactions, and for bonds between different sized atoms, especially hydrides, a wave reflection procedure is proposed that has the consequence that the less the sharing, the shorter the bond. The effects of lone pair interactions and delocalization are presented. A new hybridisation effect is proposed that, in the absence of lone pair back donation, leads to bond lengthening and weakening when n = 3 and 5.The basis of this is what I call a guidance wave. The concept of this is very similar to the de Broglie/Bohm pilot wave, but it has some significant differences. The wave function ψ is, in all quantum mechanic interpretations of which I am aware, given by ψ = A exp (2πiS/h), where S is the action, and an important point is that action evolves. That means that from Euler, the wave function becomes real at the antinode. I then make the assumption that the wave front has to travel at the same velocity as the particle, the reason being that in the two slit experiment, the diffraction does not depend on the distance to the slits and the particle should get there at the same time. That means the square of the amplitude is proportional to the particle energy and that is why you can calculate the bond properties from any position of the antinode (because the particle can only have one energy). It remains to be seen whether anyone has any interest in this, and the results are not totally accurate, nevertheless a molecule like Sb2 has a bond energy within a few kJ/mol of the calculated value. At the risk of self promotion, "The Covalent Bond from Guidance Waves" is at https://www.amazon.com/dp/B07GCDYDRR
Posted by
Ian Miller on Aug 12, 2018 3:53 AM Europe/London
