Measurements of the Diffusion and Reflection Coefficients of Cd(¹S₀) in Noble Gases

On the role of Dicke narrowing in the formation of atomic line shapes in the optical domain

“…As can be seen from figure 1 the parameter ν opt describing Dicke narrowing (obtained from the fit of the ABBP) seems to agree with ν diff (estimated using the experimental value of diffusion coefficient D [27]) up to densities of about 60 × 10 17 atom cm −3 . This could suggest that the narrowing observed in [13,15] is mainly caused by Dicke narrowing.…”

“…Since for the Cd-Xe system neither experimental nor theoretical values of D were known when the analysis reported in [13] was made, the possible influence of Dicke narrowing on the line shape was estimated to be small compared to the narrowing caused by speed-dependent effects at the highest investigated pressure of xenon, on the basis of some simulations. Recently, however, experimental values of the diffusion coefficient D for Cd-Xe were determined by Rudecki and Domysławska [27] using a method developed by Rudecki [28]. For the highest xenon concentration N = 114 × 10 17 atom cm −3 considered in our work and temperature T = 724 K they found the value D = 0.156 cm 2 s −1 .…”

“…The parameters ν opt obtained from the fit of the SDABBP and presented in figure 1 clearly demonstrate that if Dicke narrowing occurs at all in the investigated system, it is below the estimations coming from measurements of the diffusion coefficient [27] as well as from calculations based on the potential given by Czuchaj and Stoll [64]. Obviously, the value of ν opt obtained from the fit of the SDABBP to the experimental line shape depends on the assumed speed dependence of the collisional broadening and shifting.…”

“…where D 0 = 0.0253(20) cm 2 s −1 , κ = 0.99 (10) and T 0 = 273.15 K [27]. Under the conditions of the experiments described in [13] (temperature T = 724 K and the xenon density N = 100 × 10 17 atom cm −3 ) equation ( 16) yields D = 0.179 cm 2 s −1 .…”

“…Therefore we have estimated ν diff using two methods. First, we have used the results of the temperature dependence of the diffusion coefficient for the Cd-Xe system measured by Rudecki and Domysławska [27] to obtain an extrapolated value corresponding to our conditions. The temperature dependence of the diffusion coefficient of Cd in Xe at temperature T and density N 0 = 268.676 × 10 17 atom cm −3 (the Loschmidt constant) can be presented in a power-law…”