Effects of non-adiabatic and Coriolis couplings on the bound states of He(2 3S)+ He(2 3P)

The effects of non-adiabatic and Coriolis couplings on the bound states of the He(2 S-3(1))+ He(2 P-3(j)) system, where j = 0, 1, 2, are investigated using the recently available ab initio short-range (1,3,5)Sigma(+)(g,u) and (1,3,5)Pi(g,u) potentials computed by Deguilhem et al (2009 J. Phys. B: At. Mol. Opt. Phys. 42 015102). Three sets of calculations have been undertaken: single-channel, multichannel without Coriolis couplings and full multichannel with Coriolis couplings. We find that non-adiabatic effects are negligible for 0(u)(-), 0(g)(+/-), 1(u), 2(g), 2(u), 3(g) Hund case (c) sets of levels in the j = 2 asymptote but can be up to 15% for some of the 0(u)(+) and 1(g) sets of levels where near degeneracies are present in the single-channel diagonalized potentials. Coriolis couplings are most significant for weakly bound levels, ranging from 1% to 5% for total angular momenta J = 1, 2 and up to 10% for J = 3. Levels near the j = 1 and j = 0 asymptotes agree closely with previous multichannel calculations based upon long-range potentials constructed from retarded resonance dipole and dispersion interactions. Assignment of theoretical levels to experimental observations using criteria based upon the short-range character of each level and their coupling to metastable ground states produces well-matched assignments for the majority of observations. After a 1% increase in the slope of the (5)Sigma(+)(g,u) and (5)Pi(g,u) input potentials near the classical turning point is applied, improved matching of previous assignments is obtained and further assignments can be made, reproducing very closely the number of experimental observations.