Ideas of Quantum Chemistry P66 shows how quantum mechanics is applied to chemistry to give it a theoretical foundation. The structure of the book (a TREE-form) emphasizes the logical relationships between various topics, facts and methods. It shows the reader which parts of the text are needed for understanding specific aspects of the subject matter. Interspersed throughout the text are short biographies of key scientists and their contributions to the development of the field. | 616 12. The Molecule in an Electric or Magnetic Field Hartree-Fock approximation Atomic and bond dipoles Within the ZDO approximation How to calculate the dipole polarizability p. 635 Sum over states method SOS Finite field method What is going on at higher electric fields A molecule in an oscillating electric field p. 645 MAGNETIC PHENOMENA p. 647 Magnetic dipole moments of elementary particles p. 648 Electron Nucleus Dipole moment in the field Transitions between the nuclear spin quantum states - NMR technique p. 652 Hamiltonian of the system in the electromagnetic field p. 653 Choice of the vector and scalar potentials Refinement of the Hamiltonian Effective NMR Hamiltonian p. 658 Signal averaging Empirical Hamiltonian Nuclear spin energy levels The Ramsey theory of the NMR chemical shift p. 666 Shielding constants Diamagnetic and paramagnetic contributions The Ramsey theory of the NMR spin-spin coupling constants p. 668 Diamagnetic contribution Paramagnetic contribution Coupling constants The Fermi contact coupling mechanism Gauge invariant atomic orbitals GIAO p. 673 London orbitals Integrals are invariant Why is this important There is no such a thing as an isolated molecule since any molecule interacts with its neighbourhood. In most cases this is the electric field of another molecule or an external electric field and represents the only information about the external world the molecule has. The source of the electric field another molecule or a technical equipment is of no importance. Any molecule will respond to the electric field but some will respond dramatically while others may respond quite weakly. This is of importance in designing new materials. The molecular electronic structure does not respond to a change in orientation of the nuclear magnetic moments because the corresponding perturbation is too small. On the other hand the molecular electronic structure influences the subtle energetics of interaction of the nuclear spin magnetic moments and .
