Bulletin of the American Physical Society
Long range Rb{sub 2} excited state dispersion interactions and transition dipole moment from photoassociation spectra
M. Marinescu, A. Dalgarno, Chin‐Chun Tsai, Joseph D. Miller, Robert A. Cline, Daniel J. Heinzen
Abstract
Two identical alkali atoms, with one atom excited, interact at long range through the resonant dipole interaction - C{sub 3}/R{sup 3} and through the dispersion interaction - C{sub 6}/R{sup 6} - C{sub 8}/R{sup 8} - ... These interaction coefficients have been previously calculated, but not accurately measured. The authors have measured the bound levels of a unique, 0{sub g}{sup {minus}}{open_quotes} pure long range state{close_quotes} of {sub 87}Rb{sub 2} and {sup 85}Rb{sub 2} with photoassociation spectroscopy of ultracold Rb atoms. By fitting the levels predicted by the interaction Hamiltonian to the observed levels, they have derived accurate values of both C{sub 3} and of the dispersion interaction coefficients. They also obtain an accurate measurement of the Rb 5s-5p electric dipole matrix element, which is simply related to C{sub 3}. These results provide an excellent test of the theory. They are also important to cold collisions, which are very sensitive to long range interactions.