Collision broadening of the Sr-ion resonance line from the line core to the near-wing region

Profiles of the singly ionized strontium resonance line at 421.6 nm (4p ²P_1/2-4s ²S_1/2) which are collisionally broadened by argon have been measured from the line core to near-wing region (within the distance of Δν<~50 cm^-1 from the line center). The observed broadening rate of the core is (1.87+/-0.25)×10^-20 cm^-1/cm^-3 at 690 K. A clearly asymmetric profile has been observed in the wing region. These results are discussed by considering semiclassical impact and quasistatic theories combined with theoretical interaction potentials for the Sr⁺-Ar pair which were previously reported by the present authors.