Hyperfine, rotational, and Zeeman structure of the lowest vibrational levels of theRb872(1)

Abstract

We present the results of an experimental and theoretical study of the electronically excited (1) 3 + g state of 87 Rb 2 molecules. The vibrational energies are measured for deeply bound states from the bottom up to v = 15 using laser spectroscopy of ultracold Rb 2 Feshbach molecules. The spectrum of each vibrational state is dominated by a 47-GHz splitting into 0 − g and 1 g components caused mainly by a strong second-order spin-orbit interaction. Our spectroscopy fully resolves the rotational, hyperfine, and Zeeman structure of the spectrum. We are able to describe this structure to the first order using a simplified effective Hamiltonian.

Theoretical study of spin–orbit and Coriolis coupling among the low-lying states of Rb2 and Cs2

“…The negative sign and absolute magnitude of second-order SO splitting λ so = −1.4 cm −1 calculated by Eq. (2) between the 1 g and 0 − g components of the 1 3 Σ + g state of 87 Rb 2 molecule are in a good agreement with their experimental counterparts 42 − 47 GHz measured for deeply bound vibrational levels using laser spectroscopy of ultracold Feshbach molecules [44].…”

Level structure of deeply bound levels of the c3Σg+ state of Rb2

“…This is complemented by recent work of Tsai et al [20] who investigated the hyperfine structure of the weakly bound levels of c 3 Σ + g , 1 g . One important result is a partial change of our previous assignment of the spectra of measured transition lines towards c 3 Σ + g , resolving an inconsistency that was already mentioned in [19] in connection with their Fig. 7.…”

“…The molecules are irradiated for a duration of a few milliseconds by a cw grating-stabilized diode laser which resonantly excites them to c 3 Σ + g levels, leading to molecular loss. We measure the remaining number of molecules by first dissociating them into ultracold atom pairs and then measuring the corresponding atom number via absorption imaging (for details see [19,23]). By scanning the laser frequency from shot to shot, a resonance spectrum is recorded [see Fig.2b) to d)].…”

Polarizability of ultracold molecules in the rovibrational ground state of

“…In view of this discrepancy we want to estimate the influence of slight shifts of the PECs on the calculations. The potential well depths of the 1 g 3 Σ + and the 1 g 3 Π states used in the computation are smaller by 72 and 51 cm 1 − with respect to the experimental determinations of [29] and [30], respectively. Such shifts would lead to a change in the calculated polarizability of about 10% for the particular wavelengths of 830.4 and 1064.5 nm.…”

“…A full configuration interaction is then performed on the two valence electrons, using a large Gaussian basis set [28], with the CIPSI quantum chemistry code developed at Université Paul Sabatier in Toulouse. It is worth mentioning that partial spectroscopic information is available on the 1 g 3 Σ + state [29], the 1 g 3 Π state [30], and on the 2 g 3 Π state [22], but no complete PEC has been extracted in these studies. As discussed for instance in [23,30], the computed PECs are suitable to reproduce the observed data provided that they are slightly shifted in frequency (in terms of c (2 ) ω π , by at most 100 cm 1 − ).…”