Bestimmung derg J-Faktoren in den Zuständen 62 P 3/2 und 82 P 3/2 von133Cs

The hyperfine structures of the 6² P _3/2- and 8² P _3/2-states of¹³³Cs have been investigated by optical double resonance in a strong magnetic field. The Landé-g-factors and the hfs coupling constants were found to be:g _J(6² P _3/2)=1.3340(3)g _J(8² P _3/2)=1.3342(2)a(6² P _3/2)=50.02(25) MHza(8² P _3/2)=7.644(25) MHz. Contrarily to recent measurements, theg _J-factors agree well with the value calculated from the Landé formula.     

Redetermination of the hyperfine structure of the 6p 2 P 3/2 level in Cs133 by the zero field optical double resonance method

By combining recent level crossing data with the results from a modified atomic beam experiment by Buck, Rabi, and Senitzky in 1956, a Landég _j factor deviating about 0.6% from the LS-value ?1.3341 is obtained for the 6p ² P _3/2 level of Cs¹³³. As this large deviation is difficult to explain, a remeasurement of the hyperfine structure of this level was performed by the zero field optical double resonance method. For the magnetic dipole and the electric quadrupole interaction constantsa andb we obtain $$a(6p{}^2P_{{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} ) = 50.31(5)MHz,b(6p{}^2P_{{3 \mathord{\left/ {\vphantom {3 2}} \right. \kern-\nulldelimiterspace} 2}} ) = - 0.30(33)MHz.$$ With these new values ag _j factor of ?1.3341 (15) is deduced for the 6p ² P _3/2 level of Cs¹³³, in agreement with the LS-value.     

Untersuchung der Hyperfeinstruktur des 62 P 1/2-Zustandes von133Cs im starken Magnetfeld mit der optischen Doppelresonanzmethode

The hyperfine structure of the 6² P _1/2-state of¹³³Cs has been measured by optical double resonance in a strong magnetic field. From the positions of the magnetic dipole transitionsδm _J =±1,δm _I =0 theg _J -factorg _J(6² P _1/2)=0.66590(9) and the magnetic hfs-coupling constanta(6² P _1/2)=291.90(12) MHz could be derived.     

Orientation of Cs 6p 2P3/2 atomic photofragments in a magnetic field: interference in the photodissociation of diatomic molecules

In a magnetic field, Cs₂ molecules were excited from the ground X¹Σ⁺_g(v_X=0,J_X=55) level to the D ¹Σ⁺_u(v=46,J=54) level by dissociation laser light linearly polarized parallel to the field, for which the magnetic sublevels were degenerated and thus all the transitions between them were simultaneously stimulated. Probe laser light excited the dissociated Cs 6p²P_3/2 atomic fragments to 6p²D_3/2 level and the resultant 6p²P_1/2 - 6d²D_3/2 emission was detected as the function of the wavelength of the probe light. The populations of the 6p²P_3/2,mj magnetic sublevels were determined from the relative strengths of the 6p²P_3/2,mj - 6d²D_3/2,m'j transitions induced by the probe light. Non-zero orientation O₀ was found in the ensemble of dissociated Cs 6p²P_3/2 atomic fragments. The orientation O₀ increased as the magnetic field strength increased. It was demonstrated both experimentally and theoretically that the orientation O₀ was induced through the interference in the excitation and dissociation paths in the presence of an external magnetic field, even when all degenerated transitions between the magnetic sublevels of the molecules are simultaneously excited by the light linearly polarized parallel to the field.     

Measurements of theg J -factors of12C in the3 P 1 and3 P 2 states

Using the atomic beam magnetic resonance method the Zeeman interactions of¹²C in the³ P ₁ and³ P ₂ states at magnetic fields of about 3.4 kOe have been measured. The measured quantities areg _J (³ P ₁)?g_J(³ P ₂)=15.4(1.0)·10^?6 g _J (³ P ₂)=1.5010616 (50), from which the following value for g_J(³P₁) can be calculated:g _J (³ P ₁)=1.5010770 (50). The experimental results are in moderate agreement with theoretical calculations.     

Level-crossing-Experiment am 6s6p 3 P 1-Term im Ba I-Spektrum

The hfs-splitting of the stable odd Ba-isotopes Ba¹³⁵ and Ba¹³⁷ (I=3/2) in the 6s6p ³ P ₁-state was investigated by level crossing techniques. For both isotopes two crossings between Zeeman-sublevels withδm _F=2 were detected by resonance scattering of the 7911 å-intercombination line using a Ba-atomic beam. From the experimental results ratios of zero field hfs-constants and theg _J-value of the³ P ₁-state were calculated including second order corrections. The results may be compared with double resonance measurements in zero magnetic field.     

Hyperfine structure of the 8p 2 P 3/2 and 8p 2 P 1/2 levels of115In

The hyperfine structure of the 8p ² P _3/2 and² P _1/2 levels of¹¹⁵In was measured using high-resolution laser spectroscopy on a collimated indium atomic beam. Step-wise excitations from the metastable 5² P _3/2 state via the shortlived 6s ² S _1/2 state were employed. For the magnetic-dipole and electric-quadrupole interaction constantsa andb, respectively, the following results were obtained:a(8p ² P _3/2)=16.3 (3) MHz,b(8p ² P _3/2)=11 (3) MHz anda(8p ² P _1/2)=44.0 (5) MHz. The magnetic hyperfine structure is shown to be strongly influenced by core polarization. For the electric-quadrupole moment of¹¹⁵In the valueQ=0.79 (20) barn is deduced.     

Hyperfeinstrukturuntersuchung der 4p und 5p 2 P 3/2-Terme im K I-Spektrum durch Resonanzstreuung von Licht zur Bestimmung der Kernquadrupolmomente von K39 und K41

In order to determine the nuclear quadrupol moments of the stable K-isotopes, the hyperfine structure of the 4p and5p ²P_3/2-states was investigated by resonance scattering of light. The scattered intensityR(H) from separated isotopes in a sealed off resonance cell, as function of an external magnetic fieldH was observed with different polarisations (σ- andπ-components perpendicular toH) both in exciting and scattered light. Because the hfs-splitting of the investigated states is comparable to the radiation widthГ, the measured change in intensityΔR(H)/ΔH is due to interference effects (Hanle-effect, level-crossing, anti-crossing) and decoupling of electronic and nuclear spin (Heydenburg-effect). The different effects are not distinguishable in contrary to an usual level-crossing experiment and therefore the measured signal-structure is compared with line shape calculations according to Breit's-formula. Assuming “white” excitation andg _J =4/3, the measured signal-structure can be explained with the following values:Γ/2π (4p)=5.7 (4) MHzΓ/2π (4p)=5.7 (4) MHz K³⁹:A(4p)=6.13(5) MHzB(4p)=2.72(12) MHzA(5p)=1.97(2) MHzB(5p)=0.85 (3) MHz K⁴¹:A(4p)=3.40(8) MHzB(4p)=3.34(24) MHzA(5p)=1.08(2) MHzB(5p)=1.06 (4) MHz. Without Sternheimer corrections one obtains from these values Q(K³⁹)=0.062 · 10^?24 cm² and Q(K⁴¹)=0.076 · 10^?24 cm² for the electrical nuclear quadrupolmoments of K³⁹ and K⁴¹.     

Isotope shifts and hyperfine structure of the 6s-7p transitions in the cesium isotopes 133, 135, and 137

The 6s-7p transitions in cesium at 459.3 nm (7² P _1/2) and 455.5 nm (7² P _3/2) have been investigated by saturation spectroscopy in vapor cells, using a laser spectrometer with 500 kHz bandwidth in the blue spectral range. Isotope shifts as well as hyperfine splittings were determined for the isotopes 133, 135 and 137.     

Determination of theg j -factor in the72 P 3/2-state of133Cs by optical double resonance in a strong magnetic field

The hfs in the 7² P _3/2-state of¹³³Cs has been investigated by optical double resonance in a strong magnetic field. From the positions of the magnetic dipole transitions Δm _j =± 1, Δm _i =0 the magnetic hfs coupling con slanta (7² P _3/2)=16.591(25) MHz and theg _j -factorg _j (7² P _3/2)=1.33410(15) could be derived. Contrarily to recent measurements,g _j agrees well with the value calculated from the Lande formula.     

Hyperfine structure measurements in the ground states5 F 5,5 F 4,5 F 3 and5F2 of99Ru and101Ru with the atomic beam magnetic resonance method

The hyperfine structure of the four lowest levels⁵ F _{5, 4, 3, 2} of the⁵ F ground state multiplet arising from the configuration 4d ⁷ 5s in⁹⁹Ru and¹⁰¹Ru has been studied by the atomic — beam magnetic — resonance technique. After applying corrections due to the effects of off-diagonal hyperfine mixing we obtain the following multipole interaction constants:⁹⁹Ru:A(⁵ F ₅)=?204.5514(33) MHzB(⁵ F ₅)=27.281 (62) MHzA ⁵ F ₄=?163.6845(36) MHzB(⁵ F ₄)=17.455(52) MHzA ⁵ F ₃=?135.0294(37) MHzB(⁵ F ₃)=10.164(50) MHzA(⁵ F ₂)=? 82.5325(27) MHzB(⁵ F ₂)=5.457(22) MHz¹⁰¹Ru:A(⁵ F ₅)=?229.2881(33) MHzB(⁵ F ₅)=158.934(62) MHzA(⁵ F ₄)=?183.4744(36) MHzB(⁵ F ₄)=101.799(52) MHzA(⁵ F ₃)=?151.3502(38) MHzB(⁵ F ₃)=59.323(50) MHzA(⁵ F ₂)=?92.4974(27) MHzB(⁵ F ₂)=31.869(23) MHz. The magnetic dipole and the electric quadrupole moments of the⁹⁹Ru and¹⁰¹Ru nuclear ground states as calculated from these constants are the following:μ _I (⁹⁹Ru)=?0.594(119) nmQ(⁹⁹Ru)=0.077 (15) barnsμ _I (¹⁰¹Ru)=?0.666(133)nmQ(¹⁰¹Ru)=0.45 (9) barns. From measurements of the Zeeman effect in the even isotope¹⁰²Ru we find the followingg _J -factors for the⁵ F ground multiplet:g _J (⁵ F ₅)=1.397741(20)g _J (⁵ F ₄)=1.347604(20)g _J (⁵ F ₃)=1.248988(20)g _J (⁵ F ₂)=1.001120(3).     

Partial cross sections for Rb− photodetachment in the region of the Rb(5p 2 P 1/2 3/2) thresholds and their analysis by multichannel quantum defect theory

A crossed ion-laser beam apparatus has been used to measure accurate relative total and partial cross sections for photodetachment from Rb^? ions with high photon energy resolution (0.1–0.6 cm^?1) in the region of the Rb(5p ² P _1/2,3/2) thresholds (photon energy range 16,350–16,820 cm^?1). Satisfactory fits to these data by multichannel quantum defect theory (MQDT) have been obtained, resulting in a reliable set of seven MQDT parameters. The electron angular distribution parameter for the Rb(5_s) channel was found to beβ(5s)=2, independent of photon energy. MQDT predicts a sharp, window-type variation of?(5s) around the minimum of the 5s-cross section below the Rb(5p ² P _1/2) threshold (where an accurate experimental measurement ofβ(5s) was not possible) and a similar behaviour ofβ(6s) in the case of Cs^?photodetachment below the Cs(6p ² P _1/2) threshold.     

Hyperfeinstruktur des 82P3/2-Terms von Cäsium 134

The electric quadrupole interaction constantB of the 8p²P_3/2 state of Cs¹³⁴ has been determined by an optical double resonance measurement of the hyperfine structure transition v_F=11/2?F=9/2=47.84(12) Mc/s. The results are: B _8P ¹³⁴ =8.06(20) Mc/s and Q _8P ¹³⁴ =+ 0.427(8) · 10^?24cm². Comparison is made between the measurements in the 7p and 8p electronic states: Q _8P ¹³⁴ /Q _7P ¹³⁴ =0.977(20). The ratio of the corresponding Sternheimer correction factors yields the value C_7p/C_8P=0.982.     

Hyperfine structure measurements in the4 I 9/2 ground state of141Pr

Using the atomic beam magnetic resonance method, the five hyperfine structure separations in the 4f ³ 6s ^{2 4}I_9/2 ground state of ₅₉ ¹⁴¹ Pr have been measured. The results are:F F′ E _FF′ ^* /h (MHz) 7 6 6477.913423(17) 6 5 5556.359848 (6) 5 4 4633.023306 (2) 4 3 3708.201146 (5) 3 2 2782.190601(15) From these quantities, the multipole interaction constantsA _k,k=1, 2, 3, 4 between the nucleus and the electron shell have been calculated.A ₄ especially then served to give the following limit for the intrinsic hexadecapole moment: ¦Q ₄₀¦<0.4eb ². Furthermore, theg _J -factors of the⁴ I multiplet have been measured at magnetic fields of 300 Oe. The results are:g _J(⁴ I _9/2)=0.7310371(15)g _J(⁴ I _11/2)=0.9651476(20)g _J(⁴ I _13/2)=1.1063197(40)g _J(⁴ I _15/2)=1.197963 (30) Small corrections due to perturbations by neighbouring fine structure levels are included.     

Präzisionsmessung der Hyperfeinstruktur des 52P3/2-Terms und des 62P3/2-Terms von Rb85 und Rb87

To study the modification of the value of the nuclear quadrupole moment obtained without Sternheimer correction from measurements in states with different principal quantum numbers, the hyperfine structure splitting of the 5² P _3/2 and the 6² P _3/2 excited states of Rb I has been investigated with the optical double resonance method. The experiments, in which isotopic enriched samples of Rb⁸⁵ and Rb⁸⁷ were used, have been carried out in the 5² P _3/2 state without a static magnetic field. In the 6² P _3/2 state, a static magnetic field was applied. For the 5² P _3/2 state, the hyperfine structure constants areA(Rb⁸⁵)=25.029(16) Mc/s,B(Rb⁸⁵)=26.032(70) Mc/s,A(Rb⁸⁷)=84.852(30) Mc/s,B(Rb⁸⁷)=12.611(70) Mc/s. The corresponding constants for the 6² P _3/2 state areA(Rb⁸⁵)=8.25(10) Mc/s,B(Rb⁸⁵)=8.16(20) Mc/s,A(Rb⁸⁷)=27.96(35) Mc/s,B(Rb⁸⁷)=3.95(10) Mc/s. The values of the nuclear quadrupole moments, derived from both finestructure states, can be brought into agreement when the Sternheimer core correction is applied. The Landé factor for the 6² P _3/2 state isg _j=1.334(1).     

High resolution Zeeman spectroscopy on the neon levels 2s 2 and 2p 4 by mode crossing at high magnetic fields

Mode crossing signals in laser intensity occur if the Zeeman splitting of one laser level equals the frequency separation between two laser modes. This kind of experiment using two optical frequencies for double resonance yields high resolution in Zeeman spectroscopy and allows very accurate determination ofg _J -values. Mode crossing dips of the 0.633μ, 1.152μ and 1.523μ transitions of the He-Ne-laser in an axial magnetic field were measured by tuning the field strength up to 0.17 Tesla. At this field strength the Zeeman splitting of the Dopplerbroadenedσ-lines corresponds to approximately 6 Gcps. The frequency separation between resonant modes was controlled by means of a scanning high resolution Fabry-Perot. The experimental results for theg _J -values areg _J =1.2211±0.002 for the Ne 2s ₂ level andg _J =1.3008±0.002 for the Ne 2p ₄ level. A pressure inducedg _J -shift of aboutΔg _J /(g _J ×p _He)=?1.6×10^?3/Torr for the 2p ₄ level has been observed. The influence of helium collisions disturbing the Zeeman splitting of the 2p ₄ state is discussed.     

Polarisierte Anregung der metastabilen 6s 5d-Terme im Ba I-Spektrum und Messung derg J-Faktoren

In an atomic beam experiment Ba-atoms were excited in the metastable levels of the 6s 5d-configuration by optical pumping and electron impact. The three states 6s 5d ¹ D ₂ and³ D _1,2 were populated by optical excitation of the 6s 6p ¹ P ₁- and³ P ₁-level resp., which decay partly into the metastable states. The¹ D ₂- and³ D ₃-level could be excited and aligned by impact of 50 eV-electrons. Radiofrequency transitions between Zeemansublevels were detected by resonance scattering of light and theg _J-values of the four 6s 5d-levels were measured:g _J(^1D ₂)=1.0032 (2),g _J(^3D ₁)=0.4986 (2),g _J(^3D ₂)=1.1638 (2) andg _J(^3D ₃)=1.3341 (2).     

High precision measurements of theg J-factors of the alkalis using the atomic beam magnetic resonance method

Theg _J-factors of Li⁶, Li⁷, Na²³, Rb⁸⁵, Rb⁸⁷ and Cs¹³³ in their² S _1/2 ground states have been measured relative to theg _J-factor of K³⁹ with a precision of a few parts in 10⁷ using the atomic beam magnetic resonance method.     

Decay of the134Cs isomers and the levels of134Xe,134Cs,and134Ba

A precision study of the decay of¹³⁴Cs ^g and¹³⁴Cs ^m has been made, using ordinary Ge(Li) spectrometers and ā Compton-suppression spectrometer. The logft value of the second forbidden nonuniqueβ-decay to¹³⁴Xe has been measured to be 13.0±0.2. TheM4γ-ray transition in¹³⁴Cs^m(8^?) decay has been measured to haveα _K= 73±7 and a hindrance of 7.0 over the Moskowski estimate. This is discussed in terms of the level configurations and the analogous transition in¹³³Xe. A new intensity limit of 2×10^?6 has been set for the zero-phonon transition between the 4⁺ and 2⁺ members of the two-phonon triplet. This leads to an upper limit forB(E2)_4→2′, greater than 905. This and the more preciseγ-ray intensity values are discussed in relation to presently available nuclear models.     

Facteur de landé du niveau (6s26p 7s) 3P1 du plomb et constante de structure hyperfine de l'isotope 207Pb dans ce niveau

The Landé factor g_J of the (6s² 6p 7s)( ³P₁ level of the even isotopes of lead has been measured by Fabry-Pérot interferometry. The result is: g_J=1.3500(4). The agreement with the previously measured hyperfine splitting of this level for the isotope ²⁰⁷Pb and with the level crossing results is good when small corrections (nuclear Zeeman interaction, second-order hyperfine and Zeeman corrections) are taken into account. The corrected hyperfine dipole coupling constant for this level of ²⁰⁷Pb is: A=293.60(13) mK.