Purely electronic energy

Prolate symmetric top, 199, 211 Propane, dipole moment of, 225 Proper axis of symmetry, 53 Proper rotation, 395-396 Proton, 178 Pseudovector, 434 Pulse laser, 137,139 Purcell, E. M., 328, 360 Purely electronic energy, 57 Pure-rotation spectra, 165... 

This, plus the purely electronic energy ( 100,000 cm-1), is indeed above the ionization limit (which is on the, average 250,000 cm-1). 

The Bom-Oppenheimer principle (Bom-Oppenheimer approximation) [1] says that the electrons in a molecule move so much faster than the nuclei that the two kinds of motion are independent the electrons see the nuclei as being stationary, and so each electron doesn t have to adjust its motion to maintain a minimized electron-nucleus interaction energy. Thus we can calculate the purely electronic energy of a molecule, then the intemuclear repulsion energy, and add the separate energies to get the total molecular energy. 

We can treat a molecule by applying perturbation theory to the corresponding united atom, taking the perturbation H as the difference between the molecular and united-atom Hamiltonians H = H, - Hua- Using perturbation theory, one finds that the purely electronic energy of a diatomic molecule has the following form at small values of the intemuclear distance R [W. A. Bingel, / Chem. Phy, 30, 1250... 

Calculate the energy atR = 2.00 bohrs for the trial function Calculate the percent error in (a) the electronic energy including nuclear repulsion (b) the purely electronic energy (c) the dissociation energy. 

The molecular valence electronic energy f/vai including nuclear repulsion is taken as the sum of the purely electronic energy fiei,vai of the valence electrons (which is found from the results of the semiempirical SCF calculation) and the core-core repulsion energy [compare Eq. (13.8)] ... 

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