I. Diatomic Molecules

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I. Diatomic Molecules
7. Non-Crossing Rule of Potential Curves
For diatomic molecules, the potential curves
depend only on R. The noncrossing rule states
that two curves of the same symmetry do not
cross. (von Neumann-Wigner non-crossing rule)
If there is a crossing, we need
Application of the non-crossing rule Floquet
curves
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I. Diatomic Molecules
(ii) Electronic structure of H2 for fix R
1. The exact solution
The above equation is separable in elliptic
coordinates
and
Advantage of elliptic coordinates separable.
Another application atom in a static field.
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I. Diatomic Molecules
2. Another useful coordinate system for diatomic
molecular systems (Prolate spheroidal
coordinates)
2dhf is a code to calculate Hartree-Fock energy
of diatomic molecules based on this coordinates.
Advantages of this coordinates system two center
problem.
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I. Diatomic Molecules
3. LCAOLinear Combination of Atomic Orbitals
basis set vs. grid method
g bonding
The general LCAO method
A
B
u antibonding
A
B
Variation over the coefficients
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I. Diatomic Molecules
4. Correlation Diagram for H2
3d
3p
3s
2p
2p
2s
2s
1s
1s
R ? ?
R0