Encyclopedia of Geochemistry

1999 Edition
| Editors: Clare P. Marshall, Rhodes W. Fairbridge


  • D. G. Rancourt
Reference work entry
DOI: https://doi.org/10.1007/1-4020-4496-8_16

Quantum numbers

In the quantum mechanical description of microscopic systems, quantities such as the total energy, orbital angular momentum and the intrinsic spin angular moments of particles may have only certain discrete values (Cohen-Tannoudji et al., 1977). The whole and fractional real numbers that are used to enumerate these possible values are called quantum numbers. If the particular quantity is a constant of the motion (that is, if it does not depend explicitly on time and commutes with the Hamiltonian), its associated quantum number is called a good quantum number. The good quantum numbers in the simple theory (excluding fine and hyperfine interactions) of the hydrogen atom are: the principal quantum number n associated with the energy En = −me4/2h2n2, the orbital (or azimuthal) quantum number l associated with the total orbital angular momentum (squared) L2 = l(l + 1)h2, the magnetic quantum number m associated with the z-component of the orbital angular momentum Lz = mh,...


Quantum Number Hyperfine Interaction Orbital Angular Momentum Spin Quantum Offshore Engineer 
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  1. Cohen-Tannoudji, C., Diu, B. and Laloë, F. (1977) Quantum Mechanics (two volumes). New York: Wiley, 1525 pp.Google Scholar

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© Kluwer Academic Publishers 1999

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  • D. G. Rancourt

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