Stark shift correction

After taking into account the Stark shift correction, the IE for SH(A n3 2) is 84,057.5 + 3 cm (10.4212 + 0.0004 eV), as determined by the lowest possible ionization transition, that is, the Pi(l) line. This value compares favorably with the value of 10.43 + 0.03 eV obtained from the extrapolation of a short Rydberg series [196]. 

We have made a 0.8 GHz correction to the frequency scale to account for the ac Stark shift of the calibration linesIlV]. The correction is obtained by measuring the intensity of the laser in the discharge tube Cthe beam is expanded so that the uniform central portion fills the bore of the discharge tube) and applying the known ac Stark shift correction. 

For an accurate data analysis, a detailed understanding of systematic effects is necessary. Although they are significantly reduced with the improved spectroscopy techniques described above, they still broaden the absorption line profile and shift the center frequency. In particular, the second order Doppler shift and the ac-Stark shift introduce a displacement of the line center. To correct for the second order Doppler shift, a theoretical line shape model has been developed which takes into account the geometry of the apparatus as well as parameters concerning the hydrogen atom flow. The model is described in more detail in Ref. [13]. 

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 ... 

The method of symmetric points was used to determine the center of the interference curve. Extensive calculations showed that the line profile should be symmetric about the center frequency. The line center was then corrected for the second order Doppler shift, The Bloch-Siegert and rf Stark shifts, coupling between the rf plates, the residual F=1 hyperfine component, and distortion due to off axis electric fields. A small residual asymmetry in the average quench curve was attributed to a residual variation of the rf electric field across the line and corrected for on the assumption this was the correct explanation. Table 1 shows the measured interval and the corrections for one of the 8 data sets used to determine the final result. 

The observed dependence of the EA intensity is important for our analysis based on large fields and oligomers. The other entries in Table 6.7 are field-induced changes in transition moments and go as as expected from first-order corrections to the wave functions. To compare Stark shifts and intensity changes in Eq. (35), we need the widths F of the linear absorption in Fig. 6.14, since sharp features are enhanced in the derivative and / (w) has maxima around F. In the IB region, the scaling of EA(w) depends on the ratio [105]... 

Besides the total perturber fraction the three-channel QDT predicts the amplitudes of the 6snd iD2> and 6snd D2> basis vectors for the perturber itself. These amplitudes were found to be at variance with results obtained from lifetime and Stark shift measurements. The hyperfine structure of the 5d7d D2 state, shown in Fig. 12. is in excellent agreement with the three-channel QDT. We conclude that the analysis of Stark shift and lifetime measurements have to be improved to yield the correct mixing amplitudes. ... 

The shift in the energy of a quantum-mechanical system caused by an applied electric field is called the Stark effect. The first-order (or linear) Stark effect is given by (14.16), and from (14.17) it vanishes for a system with no permanent electric dipole moment. The second-order (or quadratic) Stark effect is given by the energy correction and is proportional to the square of the applied field. 

For the polar samples, the transition energy was red-shifted because of the quantum-confined Stark effect. The position of the transition energy for the nonpolar structures strictly followed the results of the calculations for a flat band model, including corrections for exciton binding energies. It is reasonable to associate this fact with the disappearance of built-in electric flelds along the (1120) growth direction. 

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