Calculations of long range interactions for 87 Sr Rydberg states

Abstract A method for calculating the properties of Rydberg states and Rydberg–Rydberg interaction between two 87 Sr atoms is described. The method is based on a multichannel quantum defect theory description of the Rydberg states that accounts for the hyperfine splitting of the 87 Sr + ground state. Results are given for the scalar and tensor polarizabilities and the eigenvalues of the C 6 matrix for the 5 sns F T = 9/2 series. These results illustrate the new features that arise due to the hyperfine splitting of the thresholds. In particular, there should be several couple Förster resonances above n = 50 unlike the case of 88 Sr which has none.