Theoretical Vibrational Energy Levels of H2 Associated with Various Combinations of Molecular-Orbital Configurations
1962; American Institute of Physics; Volume: 37; Issue: 7 Linguagem: Inglês
10.1063/1.1733299
ISSN1520-9032
Autores Tópico(s)Advanced Chemical Physics Studies
ResumoA theoretical examination has been made of the influence of various MO configurations on the spacing of the vibrational levels of H2. Eleven previously determined potential curves for the H2 ground state, based upon LC STO MO wavefunctions with configuration interaction, have been used to calculate vibrational-energy levels and their first differences ΔG. Comparison of the 11 curves of ΔG vs vibrational quantum number ν shows that only when the wavefunction contains the configuration (σu1sσu1s′) does the ΔG curve have a shape similar to that of the experimental ΔG curve. The combination of (σg1sσg1s′) and (σu1sσu1s′) provides left—right correlation or variable ionicity and this ionicity is found to vary in the same manner as the curvature of the ΔG curve. The addition of (σg2sσg2p), which gives in—out correlation, and (πu2pπ̄u2p), which provides angular correlation, to the wavefunction raises the ΔG curve especially at large ν. The use of ΔG curves obtained from simple wavefunctions to estimate dissociation energies is discussed.
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