Quasi-Relativistic Many-Particle Hamiltonians

Our aim is to develop a many-electron theory for the molecular sciences, for which we started from fundamental physical principles. Then, we realized that for this endeavor we have to compromise these first principles of quantum mechanics if we are to arrive at a stage where actual calculations on molecules and molecular aggregates are feasible. Hence, we proceed to elaborate on the two-particle interactions discussed in the preceding section and go on to derive a formalism, which captures the major part of the effect of special relativity on the numerical values of many-electron observables. 

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SO that the quasi-relativistic many-particle Hamiltonian reads... 

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