Electronic structure Stark effect

An external electric field leads to three alterations in the electron structure of an atom. Firstly, the energy levels of the atom are shifted and split (the Stark effect). The theory of this effect is well-known [8], Secondly, the highly excited states of the atom disappear. The potential for the outer electron of the highly excited atom, is equal to... 

Microwave spectra provide a rich source of minute details of molecular structures. Spectra are primarily analyzed in terms of the accurate values of the moments of inertia. This generally gives the molecular conformation and some precise structural features may emerge. To obtain a complete structure, it is necessary to measure changes in moments of inertia that accompany isotopic replacement of each atom <1974PMH(6)53>. From accurate measurements of the Stark effect, when electrostatic fields are applied, information about the electron distribution is also obtained. 

In Fig. 3 the apparatus is shown with which Stolte (1972) has performed measurements of this type NO molecules were selected with the help of electrostatic sixpole fields, in accordance with their linear Stark effect in strong fields. The source slit of 0 05 mm width has an image formed by the selected NO molecules in the plane of the detector slit which has an experimental width of 1-4 mm f.w.h.m. this width includes all disturbing effects like the magnification factor (about 18), the imperfect linear Stark effect of the NO molecules in the selected state, the finite width of the transmission of the velocity selector (Av/v = 7% f.w.h.m.) in combination with the chromatic lens errors and the directional dependence of the maximum transmitted velocity of the velocity selector. The j = nij = Q = 3/2 state was selected where 1 is the projection of the electronic angular momentum on the molecular axis. The hyperfine structure of NO influences the situation only slightly. 

Whereas the hfs can serve as a local probe for intramolecular fields and field gradients, information about the total charge-density distribution is given by the electric multipole moments, especially the dipole moment of the molecule. Both molecular properties complement each other in giving a more complete picture of the electronic structure and chemical bonding. In section IV we show a way to determine electric dipole moments from high precision Stark effect measurements. The techniques described in sections II-IV will be applicable to many other free radicals. 

This chapter deals with the electronic properties of isolated actinide atoms and ions, observed in the vapor phase at low density. The free atoms have all or most of the valence electrons present, and the spectra are due essentially to changes in the quantum numbers of the valence electrons. This is in contrast to the spectra of actinides in crystals or in solution, where the spectra are largely due to transitions within the 5f shell. In both cases, the energy level structure is dominated by the structure of the Sf shell, but in different ways. In crystals, the actinide ions are exposed to the electric field of the surrounding ions, which produces a Stark effect on the levels. The magnitude of the effect is relatively small because the field has high symmetry and, moreover, the Sf electrons are shielded from it by the 6s and... 

However, for polar heterostructures in the III-N system (i.e. for QWs or QDs grown along the [0001] direction of the noncentrosymmetric wurtzite structure), optical properties are usually dominated by the quantum confined Stark effect resulting from the internal field [5]. The confined electrons and... 

---