Stark shift splitting

B. Friedrich and D. R. Herschbach recognized that molecular axis orientation would exhibit characteristic spectra. They used laser-induced fluorescence spectroscopy to measure Stark shifts (splitting of lines by an electric field) in ICl, showing that this technique can be used to orient the ICl molecule, in spite of the fact that it is a nonsymmetric top molecule. 

In order to test the measurements of the 2S — 8S and 2S — 8D transitions, the frequencies of the 2S — 12D intervals have also been measured in Paris [49]. This transition yields complementary information, because the 12D levels are very sensitive to stray electric fields (the quadratic Stark shift varies as n7), and thus such a measurement provides a stringent test of Stark corrections to the Rydberg levels. The frequency difference between the 2S — Y2D transitions (A 750 nm, u 399.5 THz) and the LD/Rb standard laser is about 14.2 THz, i.e. half of the frequency of the CO2/OSO4 standard. This frequency difference is bisected with an optical divider [56] (see Fig. 5). The frequency chain (see Fig. 11) is split between the LPTF and the LKB the two optical fibers are used to transfer the CO2/OSO4 standard from the LPTF to the LKB, where the hydrogen transitions are observed. This chain includes an auxiliary source at 809 nm (u 370.5 THz) such that the laser frequencies satisfy the equations ... 

For the alkali-like ions the conditions concerning the Stark shift are slightly less favourable. The metastable J = 5/2 level is split into three components by the electric field. Since the energy levels lie energetically closer together, the polarisabilites are higher. A measurement has been performed in the case of Ba+ and shifts of the three components of the S 1/2 — >5/2 resonance between 6 mHz/(V/cm)2 and 12 mHz/(V/cm)2 have been found [4],... 

Whichever method is used for modulation, it also possible to measure the electric dipole moment of the molecule under investigation. This can be achieved either by measuring the separation between the unshifted and Stark-shifted lines as a function of the modulation amplitude, or by direct measurement of the Stark splitting produced by a static electric field. 

The other probabilities of photon emissions or absorptions are negligible. During the process, we remark that small transient 001 and 002 photon absorption probabilities arise. An early 002 photon absorption is observed, coinciding exactly with the (negative) shift of the transfer eigenvector. The first effects of the ( 2 pulse are indeed to (i) split the unpopulated dressed states connected to 2) and 3) and (ii) produce a Stark shift of the dressed state connected to 1) (the early part of the transfer state), which is equivalent to a partial absorption of a 002 photon. Symmetrically, a late 001 photon absorption occurs. It is due to a (positive) Stark shift of the dressed state connected to 3) (the late part of the transfer state). Arising near the end of the process, for which one 001 photon has already been absorbed, it leads to a partial absorption of a second 001 photon. At the end of the process the complete population transfer from state 1) to state 3) is accompanied by the loss of a 001 photon and the gain of a 002 photon. Thus the final result is not different from the semiclassical result. 

Chen, F.P., Hansom, D.M., Fox, D. Origin of Stark shifts and splittings in molecular crystal spectra 1. Effective molecular polarizability and local electric field. Durene and Naphthalene. J. Chem. Phys. 63, 3878-3885 (1975)... 

As a first example for the application of this technique, we mention the investigation of Stark splitting in molecules studied with a CO2 laser by Brewer etal. The authors shifted the vibration-rotation levels of by an external electric field. With increa-... 

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... 

Pochan, Baldwin and Flygare have analyzed the microwave spectra of cyclopropanone and the isotopic isomers 13Ci, 13C2, and 2,2-dideutero-cyclopropanone.63) The rotational transitions were determined by studying the Stark effect (the shifts and splittings of lines produced by an electric field). The type of transition observed for cyclopropanone was consistent with C v symmetry and the sum of the moments of inertia (/a + /b — Ic) suggested that all four protons are out-of-plane. These data eliminate such structural alternatives as the dipolar oxyallyl tautomer 82 and allene oxide 83. The electric dipole moment (fi ) was calculated to be 2.67 0.10 D, which corresponds to an average of those of acetone (2.93 D) 65> and formaldehyde (2.34D).6 )... 

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