Taxological Quantum Chemistry
Obviously, quantum mechanics has been of some help to chemists. This would have been true even in 1927 when Burrau wrote his paper on the solutions of Schrödinger’s equation for the one-electron system H 2 + . Even before the simplest problems of chemical bonding could be tackled, it was already an admirable result to have rationalized the energy levels of atoms and monatomic positive ions. Cynical people may argue that the atomic spectroscopists already had taken care of this classification relating nl-shell configurations to parity and the quantum number J, and in the case of Russell-Saunders coupling, also L and S. However, it is an oversimplification when amateur pragmatic philosophers try to convince us that a new theory is only useful if it predicts new results besides correlating the old, known facts. Even if a new theory only connects previously recognized results, it does not really matter if it is beautiful enough. The situation is rarely that of a crucial experiment so dear to text-book writers. In typical cases, when one performs hundred new experiments, the new theory may explain ten of them successfully and be indifferently compatible (and this can be a very elastic concept) with ninety of them. One most not forget that even in the most decisive type of one crucial experiment, such as that of Michelson, there are still a bunch of parallel theories compatible, e. g. the Lorentz contraction acting on rigid bodies, or Einstein’s theory of special relativity. However, the concept of special relativity is entirely different from the revolution introduced by quantum mechanics. One might imagine Blaise Pascal or Sonja Kowalewska as children inventing the special theory of relativity as an intellectually satisfactory game, whereas the necessity of quantum mechanics was a direct blow against us from reality.
KeywordsExcited Level Symmetry Type Slater Determinant Fractional Charge Crucial Experiment
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