Hydrogen quantum theory based

Two other, partially successful models to account for elemental periodicity, were proposed before and forgotten after the advent of quantum theory. An anonymous proposal, later ascribed to Prout, was based on the assumption that all atoms are composites of hydrogen. The purpose of this proposal was to account for the statistically improbable distribution of relative atomic weights, close to integer values. Following the discovery of isotopes Prout s hypothesis gained some new respectability, but it has never been fully exploited. Another theory was summarized by its author [20] in the statement ... 

Like Bohr s model of the hydrogen atom, Sommerfeld s theory flowered only briefly. The creation of quantum mechanics and the discovery of electron spin, both in 1925, followed by Paul Dirac s theory in 1928, provided a solid theory-based underpinning for... 

Ab initio methods (11). derived from the beginning premises of quantum theory, is one of the quantum mechanical calculations based on the Hartree-Fock self-consistent field theory with one-electron molecular orbital. This method that uses no experimental data is based on variation theory to seek the nuclear geometry of the molecule or hydrogen-bonded complex with lowest energy. 

Keywords Bond path Bond critical point Laplacian of the electron density Hydrogen bond Halogen bond Pnicogen bond Lewis acid-Lewis base interaction Quantum Theory of Atoms in Molecules (QTAIM) Natural Bond Orbitals (NBO) method o-hole concept Electrostatic potential... 

In 1913 Bohr published a theory of the hydrogen atom, based on unproved assumptions. We regard his theory as the third part of the old quantum theory. A simplified version of Bohr s assumptions is ... 

The Bohr theory gives the correct energy expression for the hydrogen atom. Like the other theories of the old quantum theory, it is based on unproved assumptions, not all of which have turned out to be correct. Bohr was unable to extend the theory to apply to the helium atom or any other atom, and it became obvious that the theory was inadequate. However, it and the other theories of the old quantum theory provided the incentive for others to find a more satisfactory theory. 

Modern quantum theory, also called quantum physics or quantum mechanics, replaced Bohr s theory in 1926. Quantization arises naturally by using quantum mechanics. It is not assumed or imposed beforehand as a condition, as was done by Bohr. As we will soon see, the circular orbits that are so prominent in Bohr s model of the hydrogen atom are absent in the model based on quantum mechanics. Despite the fact that Bohr s model of the hydrogen atom is wrong, it was an important scientific development because it prompted a paradigm shift—the quantum leap—from classical physics to the new quantum physics. 

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