文档介绍：The Electronic Structure of Atoms: From Quantum Numbers to The
Periodic Table
Massive atomic nuclei are born naked, but positive charge, Z, quickly attracts Z
comparatively massless electrons to produce neutral atoms. The electrons do not "nuclear
react" with the protons in the nucleus (as they do inside neutron stars), instead they
associate as three dimensional resonant standing waves; a subtle quantum mechanical
dance about the point positive charge.
The modes of resonance for single electron systems (such as the hydrogen atom) are
described by the Schrödinger wave equation. Very briefly Schrödinger knew of de Broglie's
proposal that a moving particle has wavelength, l, proportional to Plank's constant, h, and
its momentum p so that l = h/p (a property now known as wave-particle duality).
With this idea in mind, Schrödinger constructed a differential equation for a wavelike
electron resonating in three dimensions about a point positive charge. Solutions to the
Schršdinger wave equation correspond to modes of electron resonance and are formally
called wavefunctions. Wavefunctions assume discrete, or quantised, energies and have
energies which correspond to the spectral lines of one electron atoms and ions of the type:
H•, He+, Li2+, Be3+, etc.
Wavefunctions are generally called orbitals by chemists, but actually more than just a
name change takes place. The problem is that the Schrödinger wave equation can only be
solved analytically for one electron systems. For multi-electron systems it is necessary to
use approximations, and the more electrons the more severe are the approximations. A
more fundamental difficulty is that there are several formulations of quantum mechanics,
including Heisenberg's matrix mechanics, but orbitals only arise in the Schrödinger
approach.
The chemist's orbital is actually a conceptual model, but one which is enormously useful
for thinking about atomic and molecular structure. Mathemati