Photoassociative Spectroscopy as a Self-Sufficient Tool for the Determination of the Cs Triplet Scattering Length

Abstract

In photoassociation spectroscopy, the line intensities of a given vibrational progression exhibit zero-signal modulation reflecting the node structure of the s-wave ground state wave function of two free colliding atoms. This leads to the determination of the scattering length. We performed photoassociation of cold Cs atoms polarized in the Zeeman sublevel f = 4, m(f) = 4. We analyzed the intensities of the lines associated with the Cs2 0(-)(g) state dissociating to the 6s(1/2)+6p(3/2) asymptote. This yields a value of the Cs triplet state scattering length, a(T) = -530a(0), while consistency requirements impose a value of the multipole ground state molecular coefficient, C6 = 6510 a.u.

High-precision calculations of van der Waals coefficients for heteronuclear alkali-metal dimers

“…In Fig. 2 we present for the dispersion coefficients of the dimers involving Cs a comparison between our calculated values and the most recent determinations [6,30]. We give the percentage deviation from our calculations.…”

“…[6] (square) and Ref. [30] (diamond). [34] 2519(10) a Ishikawa et al, [38] 2646(31) a Ross et al, [39] 2669.4(20) a a Experiment.…”

Frequency shifts of photoassociative spectra of ultracold metastable helium atoms: A new measurement of the s -wave scattering length

“…Since the development of laser cooling techniques which provide sub-millikelvin ultracold atomic samples, the photoassociation of such atoms has been of much interest and provides detailed information on the inter-atomic interaction and collisional properties [1]. The measurement of the PA spectra allows very precise measurement of the s-wave scattering length [2][3][4][5], a crucial parameter for understanding the collisional properties of the ultracold atoms or molecules and the dynamic behavior of the condensate.…”

Photoassociation spectroscopy of ultra-cold long-range molecules

“…The PA rate depends on the overlap integral S(α, v) = α|v between the (energy-normalized) radial wavefunction of the initial continuum state α, and the bound wavefunction of the final vibrational level v. For long-range excitation (corresponding to large v) the Franck-Condon factor |S(α, v)| 2 is, to very good approximation, proportional to |ψ α (R T )| 2 , the square of the modulus of the radial wavefunction ψ α of the two colliding atoms taken at the classical outer turning point, R T , of the final ro-vibrational level. We thus expect important variations in the PA rate, with quasi-zero efficiency when the classical outer turning point, R T , corresponds to a node of the radial wavefunction, ψ α [25]. Fig.…”

“…We also remark the modulation of the line intensities, which is due to the variations of the Franck-Condon factors of the transitions between the initial state and the final ro-vibrational levels of the 0 − g state. This modulation can be used for the determination of collisional parameters such as scattering lengths [25,31].…”