Geometry dependence, of the Hamiltonian

So far we have considered the Hamiltonian at one geometry, as appropriate for single-point calculations. However, if we wish to calculate the derivatives of the energy with respect to variations in the geometry, we must also consider the geometry dependence of the Hamiltonian. This introduces certain complications, which are treated in the remainder of this section. 

The geometry dependence of the Hamiltonian js isolated in the integrals. It only remains to determine the explicit form of h( and g(pqrs. 

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