Two-photon spectroscopy of some even-parity levels in neutral ytterbium

Abstract

Using Doppler-fm tw-photon excitation from the ground state 4fi46s2 'So the even-parity J = 2 levels of the 4f1'6s7d and 4f1'6s8d configurations as well e w the 4f1'6p2, 4f136s26p and 4fI35d6s6p configurations between 44760.4 and 47341.8 cm-' in neutral ytterbium have been investigated with regard to the hyperfine structure of the excited states and the isotope shift of these transitions. The experimental results for the hyperfine splitting constants have been analysed regarding passible singlet-triplet and configuration mixing. The experimental values have been compared with theoretical results obtained in an ab initio calculation. A strong iduence for the second-order hyperfine interaction could be established in both the 4f1'6r7d 3D2 and the 4f1'6s1Os 'So states.

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

“…At the first glance excellent agreement between (14)j (a) calculated with the MQDT parameters in of the theofrom Ref. [30] -194.02 (18) 157.248 (34) 139.542 (28) 115.29 (13) 91.067 (11) 67.954 (69) Experiment B (MHz) 4.49 (57) 3.ss(is) 6.59(so) 24 For the transitions 5s So -+ 5snd D2 in Sr I this is true only for the even isotope pairs. As an example, Fig.…”

“…Here I and J are the angular momenta of the nucleus and the electrons, respectively. Evaluating this matrix element, one obtains the well-known Casimir formula [28] -', K(K+ 1) -J(J + 1)I(I + 1) 2 2I(2I -1)J(2J -1) (5) where (18) sible since for first-order perturbation theory the center of gravity of a hyperfine multiplet remains unshifted…”

“…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].…”

The hyperfine structure in the configuration 4f 135d6s6p in ytterbium

“…But the 4f shell can easily be broken leading to a great number of states of the configurations 4f 13 nl n l n l which can be expected to perturb the states of the two-electron configurations 4f 14 nl n l [2]. Extensive experimental work has been done in the past on the investigation of the hfs in the two-electron system which is compiled in the introduction of [2].…”

“…But the 4f shell can easily be broken leading to a great number of states of the configurations 4f 13 nl n l n l which can be expected to perturb the states of the two-electron configurations 4f 14 nl n l [2]. Extensive experimental work has been done in the past on the investigation of the hfs in the two-electron system which is compiled in the introduction of [2]. In recent years the hfs in several states of the configuration 4f 13 5d6s6p has been determined with different methods: Two photon transitions starting from the ground state have been detected in a thermionic diode [2], [3], transitions between various states of the configuration 4f 13 5d6s 2 and 4f 13 5d6s6p have been observed by optogalvanic spectroscopy or by laser induced fluorescence in a hollow cathode gas discharge [4].…”