Electrons angular momentum

Now, we have besides the vibrational, the electronic angular momentum the latter is characterized by the quantum number A corresponding to the magnitude of its projection along the molecular axis, L. Here we shall consider A as a unsigned quantity, that is, for each A 7 0 state there will be two possible projections of the electronic angular momentum, one corresponding to A and the other to —A. The operator Lj can be written in the form... 

The first application of quantum theory to a problem in chemistry was to account for the emission spectrum of hydrogen and at the same time explain the stability of the nuclear atom, which seemed to require accelerated electrons in orbital motion. This planetary model is rendered unstable by continuous radiation of energy. The Bohr postulate that electronic angular momentum should be quantized in order to stabilize unique orbits solved both problems in principle. The Bohr condition requires that... 

Thus, each atom experiences a force which is proportional to the z-component of its electronic angular momentum. By measuring the deflection of the beam Fz can be calculated. 

In his last paper Dunham obtained a formula for values of spectral terms for a particular isotopic species i in a particular electronic state, which we suppose generally to be of symmetry class 2 or 0 implying neither net electronic orbital nor net intrinsic electronic angular momentum ... 

E are the projections of the electron orbital angular momentum on the molecular axis and the subscript is the projection of the total electron angular momentum on the molecular axis directed from the heavy atom to fluorine. It is convenient to describe the spin-rotational spectrum of the ground electronic state in terms of the effective spin-rotational Hamiltonian following [90, 117] ... 

If J is the quantum number for the total electronic angular momentum, then the magnetic moment is given by... 

One-electron angular momentum operator corresponding to direction y. 

Nuclear spin Total electron angular momentum I I nti... 

In L-S coupling, the total electronic angular momentum (spin and orbital) is defined by the quantum number J whose allowed values are... 

Most molecules with A>0 obey Hund s case (a). Here, the axial components of electronic orbital angular momentum (Ah) and of electronic spin angular momentum (2fc) combine to give a resultant axial component of total electronic angular momentum (A + 2)fi. The quantum number ft is defined as (Section 1.19)... 

The presence of degenerate vibrational modes affects the rotational energies. In Section 4.11, we saw the effect of electronic angular momentum on the rotational energies of a diatomic molecule. In this section, we shall assume that there is no electronic angular momentum, only nuclear vibrational and rotational angular momentum. If both electronic and... 

We now consider many-electron atoms. We will assume Russell-Saunders coupling, so that an atomic state can be characterized by total electronic orbital and spin angular-momentum quantum numbers L and S, and total electronic angular-momentum quantum numbers J and Mj. (See Section 1.17.) The electric-dipole selection rules for L, J, and Mj can be shown to be (Bethe and Jackiw, p. 224)... 

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