Electron correlation effects in even Rydberg series converging to 4f13(2F7/2°)6s(7/2,1/2)4° and 4f13(2F7/2° )6s(7/2,1/2)3° of thulium atom

In the frame work of multi-channel quantum defect theory (MQDT), the energy levels of three even Rydberg series 4f(13)(F-2(7/2)degrees)6s(7/2, 1/2)(4)degrees np(3/2), 4f(13)(F-2(7/2)degrees)6s(7/2, 1/2)(3)degrees np(3/2) and 4f(13)(F-2(7/2))6s(7/2, 1/2)(3)degrees np(1/2) converging to 4f(13)(F-2(7/2))6s(7/2, 1/2)(4)degrees or 4f(13)(F-2(7/2))6s(7/2, 1/2)(3)degrees of thulium atom are calculated by relativistic multi-channel theory. Compared with the experimental data from National Institute of Standards and Technology (NIST), the theoretical result shows two different types of electron-correlation effects: 1) the interaction between two Rydberg series results in energy shifts for these Rydberg series; 2) an isolated perturbed state is embedded in the energy range of a Rydberg series and interacts with the whole series, and breaks the regularity of the Rydberg series, and quantum defects show a large jump around the perturbed state. More specifically, by comparing the present calculated quantum defects with the experimental data, we reassign two Rydberg series: 1) 4f(13)(F-2(7/2))6s(7/2, 1/2)(4)degrees np(3/2) Rydberg series from NIST is reassigned as 4f(13)(F-2(7/2))6s(7/2, 1/2)(4)degrees nf(5/2), J(pi) = (5/2)(+), 4f(13)(F-2(7/2))6s(7/2, 1/2)(4)degrees nf(5/2), J(pi) = (7/2)(+) and/or 4f(13)(F-2(7/2))6s(7/2, 1/2)(4)degrees np(1/2), J(pi) = (9/2)(+) Rydberg series, and the difference between experimental and calculated quantum defects is generally better than 0.1; 2) 4f(13)(F-2(7/2))6s(7/2, 1/2)(3)degrees np(3/2) Rydberg series from NIST is reassigned as 4f(13)(F-2(7/2))6s(7/2, 1/2)(3)degrees nf(7/2), J(pi) = (5/2)(+), 4f(13)(F-2(7/2))6s(7/2, 1/2)(3)degrees nf(7/2), J(pi) = (7/2)(+) and/or 4f(13)(F-2(7/2))6s(7/2, 1/2)(3)degrees nf(5/2,7/2), J(pi) = (9/2)(+) Rydberg series, and the difference between experimental and calculated quantum defects is generally better than 0.05. As for the 4f(13)(F-2(7/2))6s(7/2, 1/2)(3)degrees np(1/2) Rydberg series from NIST, we find there is a perturbed state at about 49900 cm(-1), and assign the perturbed state as 4f(13)(F-3(4))6d(5/2) 6s(2), J = 7/2 and the total angular momentum for the Rydberg series is J = 7/2.