Laser-atomic-beam spectroscopy of 4f 75d6s?4f 75d6p transitions in Eu I

Abstract

The hyperfine structure and the isotope shift of transitions between metastable levels of the configuration 4fV5d6s and levels of the configuration 4f75d6p of lS~Eu and lS3Euwere studied by means of the high resolution laser-atomic-beam technique. The metastable states were populated by an arc discharge burning in the atomic beam. The measured hyperfine constants A and B of the 4f75d6s configuration allow to perform a parametric analysis using the effective tensor operator formalism. For the first time the nuclear quadrupole moments are deduced from the quadrupole interaction parameters of the 5d electron in EuI. The values uncorrected for the Sternheimer effect are ~S1Q(5d)=l.53(5)b and lSSQ(5d)=3.92(12)b. A comparison with the quadrupole moments derived from the 6p electron and the intrinsic quadrupole moment of 153Eu gives information about Sternheimer's correction factors. The value found for the hyperfine anomaly due to s electrons in the 4f75d6s configuration agrees very well with previous results in other Eu configurations. The change in the mean-square nuclear charge radius is derived from the isotope shift measurements and compared with the results obtained from other optical transitions in Eu. The mean value is a<r2) ~5~.~53 =0.577(25) fm z.

Nuclear spins, moments, and changes of the mean square charge radii of140?153Eu

“…5 have been calculated by using the standard formula including the quadrupole deformation /32 with conserved nuclear volume * Q'A5d) have been reported by Brand etal. [28] for EuI and by Arnesen etal. [37] for Eull; owing to the uncertainty about R(5d), as discussed in [28], these values are not included in our discussion 6(r2) "~.'"…”

“…The comparison of our 2 i5i'153 and 2 ts''152 values with earlier reported works [16,18,28,29] is shown in Table 5.…”

Determination of isotope shift crossed-second-order-effects and hyperfine-structure parameters in the Eu I configuration 4f 7 6s7s

“…The parameter al~ can also be compared with the corresponding values of the configuration 4fV6s6p [7] (al~ The fact that both values are not very different shows that an influence of the outer s-or p-electrons on the parameter al~ should be more or less equal, whereas the al~ (=-3.61(9)mK) of the configuration 4f75d6s [13] seems to point to a considerable influence of the 5 d-electron. Also interesting is a comparison of the al~ -parameters of various configurations in Eu ( Table 5).…”

“…(Since this hfs-analysis is carried out on the basis that the parent term (4f 7) is a pure sS7/2 the hfs 426 [10,13] contribution of the 4f-electrons is expressed by the one parameter al~ only). From a least-squares-fit we obtain the following results: a~~ -2.10 (4) inK, al~ = 397.3 (5) mK, al~ = 64.2(3)mK.…”

Hyperfine structure constants and isotope shift of the levels of the configuration 4f 6 5d 6s 2 in Eu I

“…Until now the hyperfine structure (hfs) and the isotope shift (IS) of the levels belonging to configurations: 4 f 7 6s 6p [1][2][3], 4 / 7 5d 6p [-4, 5], 4 / 7 5d 6s [6][7][8][9][10], 4f76d6s [I1], 4f76s7s [12] and 4f76sSs [1][2][3][4][5][6][7][8][9][10][11][12][13] have been investigated with high accuracy by laser-spectroscopic methods in both stable europium isotopes 15~Eu and 153Eu" The hfs of the ground level 4 f 7 6s 2 SS7/z has been very accurately measured by atomic-beam-methods [-14, 15]. Recently Childs [16] using atomic-beam laser-rf double-resonance technique obtained also very precise values for the hfs splitting in ten 4f75d6s I°Dj and SDj levels of the ~ 51,153Eu I.…”