6533b836fe1ef96bd12a1c1e

RESEARCH PRODUCT

The branching ratio of intercombination A1Σ+∼b3Π→a3Σ+/X1Σ+transitions in the RbCs molecule: Measurements and calculations

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Abstract We observed the A 1 Σ + ∼ b 3 Π → a 3 Σ + / X 1 Σ + laser-induced fluorescence (LIF) of the RbCs molecule excited from the ground X 1 Σ + state by the Ti:Sapphire laser. The LIF spectra from the common perturbed levels of the singlet-triplet A ∼ b complex was recorded by the Fourier-transform (FT) spectrometer with the instrumental resolution of 0.03 cm − 1 . The relative intensity distribution in the rotationally resolved A ∼ b → a 3 Σ + ( v a ) / X 1 Σ + ( v X ) progressions was measured, and their branching ratio was found to be about of 1 ÷ 5 × 10 − 4 in the bound region of the a 3 Σ + and X 1 Σ + states. The experiment was complemented with the scalar- and full-relativistic calculations of the A / b − X / a transition dipole moments (TDMs) as functions of internuclear distance. The relative systematic error in the resulting ab initio TDM functions evaluated for the strong A − X transition was estimated as few percent in the energy region, where the experimental LIF intensities are relevant. The relative spectral sensitivity of the FT registration system, operated with the InGaAs diode detector and CaF beam-splitter, was calibrated in the range [6 500, 12 000] cm − 1 by a comparison of experimental intensities in the long A ∼ b → X(vX) LIF progressions of the K2 and KCs molecules with their theoretical counterparts evaluated using the ab initio A − X TDMs. Both experimental and theoretical transition probabilities can be employed to improve the stimulated Raman adiabatic passage process, a → A ∼ b → X, which is exploited for a laser assembling of ultracold RbCs molecules.