Hyperfine-induced singlet-triplet mixing in 3He

Isotope shifts of perturbed 6sns 1 S 0 and3 S 1 Rydberg states of odd barium isotopes

“…In the upper part (Fig. 5a), the isotope shifts IS' for the transition 6sZ~6sns 1S o corrected for the normal mass shift of this twophoton transition 6v't37-t38(6sZ_6sns tSo)=&v137 -138 +6vz137-138 _ ~ .. VNMS 137-138 (11) have been plotted for principal quantum numbers 11_<n_<23. Fig.…”

“…More recent studies of these effects involving the same isotopes were reported by Landais [9] and Gerstenkorn and Verghs [10]. An especially simple example for hyperfine-induced singlet-triplet mixing represents 3He, for which Liao et al [11] investigated the hyperfine structure of the ls 3d 1, 3Dz states. Although these hyperfine-induced shifts were generally termed as second order hyperfine contributions, in this paper we prefer to speak of hyperfine-induced isotope shifts, since for highly excited Rydberg states, second order perturbation theory might not be applicable.…”

Second-order magnetic contributions to the hyperfine splitting of the 5snd1D2Güdde1, Klinkmüller2, West3 et al. 1993Phys. Rev. A41340View full textAdd to dashboardCite

“…Previously, the effects of higher-order contributions to the hfs in Rydberg states due to neighboring fine structure levels have been observed in Hg 3 -5], sHe [6], Ca [7], Sr [2, 7 -10], Ba [2, 7, 11 -15], Sm [16,Pb [17], and Yb [18]. For very high Rydberg states the energy spacing of states with different principal quantum number n is small enough to cause hyperfine-induced mixing [19 -21].…”

Mesure de la structure hyperfine des niveaux 3 1D2, 4 1D2 et 5 1D2 de l'hélium 3

“…Les termes de l'hamiltonien de structure fine et hyperfine qui couplent les niveaux nID et n 3D dans 3He peuvent être écrits (cf. appendice 2.1) [2,7] :…”

“…Dans une première approche, on s'attendrait à la trouver presque nulle, tout au plus de l'ordre de 1 MHz, car l'interaction hyperfine dans les niveaux singulets ne devrait être due qu'à l'électron externe [1,2]. En réalité, les structures observées sont de l'ordre de 100 MHz [3][4][5][6] ; elles résultent du fait que les interactions spin-orbite et hyperfine ne sont pas très faibles vis-à-vis de la distance entre triplet et singulet, de sorte que les niveaux singulets sont en réalité appréciablement mélangés aux niveaux triplets [2,4,5,7].…”