Theoretica chimica acta

, Volume 20, Issue 3, pp 282–291 | Cite as

Calculation of the energies of the lower excited states of CH3

  • Ruth McDiarmid


Ab initio LCAO-MO-SCF calculations have been performed on assorted low-lying configurations of the CH3 radical to assess the adequacy of the Hartree-Fock treatment of this species. The 2E′ configuration of lowest energy in the planar ground state equilibrium geometry is shown not to be the valence configuration. Near its (pyramidal) equilibrium geometry the 2E′ valence configuration is well below the other 2E′ configuration. The two 2E′ configurations must, then, cross as the molecule is distorted. In this region the Hartree-Fock formation is unable to describe 2E′ states. The other low-lying states [2A′'2 (ground), 2A1 (3s Rydberg), and 1A1 (ion)] and the 2E′ states in the pyramidal geometry are satisfactorily determined within the Hartree-Fock formalism.


Inorganic Chemistry Organic Chemistry Lower Energy Excited State State Equilibrium 
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Die Resultate von ab initio-Rechnungen für das CH3-Radical für die tiefliegenden Konfigurationen werden angegeben. Die Konfiguration des tiefsten 2E′-Zustandes resultiert allerdings bei planarer Geometrie nicht aus der Elektronen-Grundkonfiguration. Letztere ist zwar bei fast pyramidaler Struktur wesentlich tiefer, schneidet aber erstere im Verlauf der Verzerrung des Moleküls. In dieser Region ist die HF-Näherung nicht mehr gültig. — Die anderen tiefliegenden Konfigurationen [2A″2 (Grund-Konfiguration), 2A1 (3s Rydberg) und 1A1 (Ion)] verhalten sich normal.


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Copyright information

© Springer-Verlag 1971

Authors and Affiliations

  • Ruth McDiarmid
    • 1
  1. 1.National Institute of Arthritis and Metabolic DiseasesNational Institutes of HealthBethesda

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