Absorption profiles of cesium resonance lines at 8521 and 8944 \AA{} have been measured for the wavelength range from 0.5 to 30 \AA{} from the line centers using a tungsten ribbon light source, cell lengths
L from 0.31 to 6.1 cm, and Cs densities
N from 2 \ifmmode\times\else\texttimes\fi{}
1014 to 2 \ifmmode\times\else\texttimes\fi{}
1016 ${\mathrm{cm}}^{\ensuremath{-}3}$. The wavelength dependence of the absorption coefficients are consistent with a Lorentzian form and values of $\frac{\ensuremath{\gamma}f}{N}=1.08\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ and 0.30 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}7}$
cm3 ${\mathrm{sec}}^{\ensuremath{-}1}$ are obtained for 8521 and 8944 \AA{} lines. Here $\ensuremath{\gamma}$ is the collisional (or Lorentzian) half-width and
f is the oscillator strength. The values of $\frac{\ensuremath{\gamma}f}{N}$ deduced from total fractional absorption data agree with those determined from the line profiles. Our results agree well (to within 15%) with those of Gregory and with theory, but disagree with more recent data. A source of error in some previous determinations of half-widths is the fact that even when the calculated absorption is very large, the measured transmission at the line center is significant; about 3.5 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}2}$ compared to \ensuremath{\sim} ${10}^{\ensuremath{-}100,000}$ predicted from our measurements in the wings of the lines for $N=1.14\ifmmode\times\else\texttimes\fi{}{10}^{15}$ ${\mathrm{cm}}^{\ensuremath{-}3}$ and
L=5.9 cm. This effect is shown to result from transmission through the monochromator at wavelengths in the far wings of the instrument function.
Abstract The absorption coefficients of the statistical wings of the Cs principal series lines 6 2S1/2 - n 2P3/2 (6 ≦ n ≦ 10) and 6 2S1/2 - n 2P1/2 (6 ≦ n ≦ 9) perturbed by Xe have been measured quantitatively The results are compared with quasistatic line wings calculated from the interatomic Cs -Xe potentials of Baylis 1 and Pascale and Vandeplanque 2. In the far wings of the higher lines of the series indications of many-body interaction were found. Furthermore the behaviour of the shift of all principal series lines up to the 23rd member was investigated in the density region between 1.63 X 1018 and 1.9 X 1019 Xe atoms per cm-3.
In addition to previous absorption measurements of Cs resonance lines, new investigations on Na, K and Rb also showed definitely that beyond symmetrical Lorentzian central parts of the lines, the stronger components of the resonance lines have blue and the weaker components red asymmetry. This behaviour can be explained by a quasistatic treatment of the self-broadening mechanism taking interatomic interaction potentials into account. But with additional data it is now possible to give a different interpretation of the origin of observed asymmetries than suggested in the previous paper on Cs resonance lines (see abstr. A5740 of 1975). The asymmetries are shown to arise from the mutual repulsion of two potential curves of the same species.
Reduced absorption coefficients γBaBa were measured for the far-wing absorption of the self-broadened Ba6s2 1S0–5d6p 1P1 line, Ba(6s2 1S0) +Ba(6s2 1S0)+ℏω → Ba*(5d6p 1P1)+Ba(6s21 S0)and the pair absorption Ba(6s2 1S0)+Ba(6s2 1 S0) +ℏω→Ba*(6s6p 1P1 +Ba*(6s5d 1D2). The self-broadening shows the red-shaded asymmetric profile: γBaBa on the red wing is proportional to Δν−3/2, where Δν is the detuning from the line center. The pair absorption shows a broad asymmetric peak having a blue tail and a blue satellite. The estimated γBaBa, which is based on the quasistatic line-broadening theory and the long-range dipole–dipole interaction between the relevant atomic excited levels, shows reasonable agreement for the red wing of the self-absorption whereas it gives larger values by a factor of 3 for the blue tail of the main peak for the pair absorption.
Recent absorption measurements of the self-broadening of Rb principal series lines [C. H. Greene, E. L. Hamilton, H. Crowell, C. Vadla, and K. Niemax, Phys. Rev. Lett. 97, 233002 (2006)] verified the existence of minima in highly excited long-range potentials of
Rb2 which were predicted theoretically as bound Rydberg molecule [C. H. Greene, A. S. Dickinson, and H. R. Sadeghpour, Phys. Rev. Lett. 85, 2458 (2000)]. The present paper reports on the extension of these experimental studies to principal series lines of K broadened by K as well as Cs broadened by Cs. In addition, the broadening of some lower members of the K, Rb, and Cs principal line series due to heteroatomic interactions was investigated. The analysis of the measured satellite structures in the quasistatic line wings and their comparison to the previously published analogous data for ${\text{Rb}}^{\ensuremath{\ast}}+\text{Rb}$ system lead to the conclusion that one can expect existence of potential minima in homo- and heteroatomic alkali-metal ${A}^{\ensuremath{\ast}}+B$ systems in a wide range of principal quantum numbers, starting with K, Rb, and Cs excited to the third resonance states. The positions and strengths of the satellite structures indicate that the potential minima are due to scattering of the valence electron by ground-state perturbers.
The authors have measured the absorption efficient in the quasi-static wings of the first potassium resonance lines in various K-Cs mixtures. At sufficiently high concentrations of caesium atoms both components of the potassium first resonance doublet have extended blue wings of the van der Waals type. The corresponding effective C 6 constants determined from the experimental data are (1.5+or-0.3)*10 -29 s -1 cm 6 and (2.4+or-0.5)*10 -29 s -1 cm 6 for the stronger and weaker components, respectively. The calculated values of the effective C 6 constants are 1.78*10 -29 s -1 cm 6 for the stronger component and 2.35*10 -29 s -1 cm 6 for the weaker component.