We present a detailed study of the $0_g^{-}{(P}_{3/2})$ pure long-range electronic state of the ${}^{87}{\mathrm{Rb}}_2$ molecule. The high-resolution spectral data provided by photoassociative spectroscopy of ${}^{87}{\mathrm{Rb}}_2$ is analyzed by using the generalized simulated annealing method. The dipole matrix element of the $5p$ ${}^{87}\mathrm{Rb}$ atomic state and other effective asymptotic parameters for the $0_g^{-}{(P}_{3/2})$ long-range state are determined and a complete analytical description of the potential well is obtained. We extract a radiative lifetime of the ${5P}_{3/2}$ and ${5P}_{1/2}$ states equal to 26.25(8) ns and 27.75(8) ns, respectively, with a precision (0.3%) comparable to atomic physics experiment.

• Received 5 September 2001

DOI:https://doi.org/10.1103/PhysRevA.66.024502