Levelcrossing experiments in the first excited1 P 1 states of the alkaline earths

The hyperfine structure of the lowest¹P₁ state of²⁵Mg,⁴³Ca,⁸⁷Sr,¹³⁵Ba and¹³⁷Ba have been measured by the level-crossing and anticrossing technique. The magnetic dipole and electric quadrupole coupling constants determined by these measurements are²⁵Mg(3s3p¹P₁):A=? 7.7(5) MHz; 16 MHz>B>0 MHz,⁴³Ca(4s4p¹P₁):A=? 15.3(4) MHz; ¦B¦<12 MHz,⁸⁷Sr (5s5p¹P₁:A=? 3.4(4) MHz;B=39(4) MHz,¹³⁵Ba(6s6p¹P₁):A=? 97.5(1.0) MHz;B=31(9)MHz,¹³⁷Ba(6s6p¹P₁):A=?109.2(1.2) MHz;B=51(12)MHz. The results have been compared with the predictions of the Breit-Wills theory of the two-electron hyperfine structure using the experimental data on the³P states. Large discrepancies have been observed which are due to different radial wave functions of thes andp electron in the triplet and singlet system. This effect has been taken into account by fitting the data with the aid of two additional parameters. That this procedure is justified is shown by an analysis of the fine structure splitting, the life times, and the isotopic shifts in thesp configurations of group II elements.     

Solution of Faddeev-type equations in the problem of two coulomb centers

The hyperfine structure of the 7p ² P _1/2,3/2 levels of¹¹⁵In and the 5p ² P _1/2 level of²⁷Al has been measured using high-resolution laser spectroscopy on atomic beams. For the magnetic-dipole and electric-quadrupole interaction constants,a andb, the following values were obtained;a(7p ² P _1/2)=90.7(10) MHz,a(7p ² P _3/2)=32.3(2) MHz andb(7p ² P _3/2)=24.5(1.5) MHz for¹¹⁵In anda(5p ² P _1/2)=20(2) MHz for²⁷Al. Many-body calculations on² P states in aluminum, gallium and indium have also been performed.     

Analysis of the isotope shifts and hyperfine structure in the 3 988 Å (6s6p 1 P 1↔6s 2 1 S 0) YbI line

High-resolution laser spectroscopy using a pulsed dye-laser acting on a collimated atomic beam has been used to determine the isotope shifts in the 3 988 Å YbI line. The following results have been obtained:Δσ(176, 174)=?509(4)MHz,Δσ (174, 173)=?291(10) MHz,Δσ(174, 172)=?530(4) MHz,Δσ(172, 171)=?414(5) MHz andΔσ(172, 170)= ?665(10) MHz. The sign of the magnetic dipole interaction constant in the¹ P ₁ state for¹⁷¹Yb is found to be negative,a(¹ P ₁, 171)=?213.4(3.0) MHz. The electric quadrupole interaction constant for¹⁷³Yb in the¹ P ₁ state is found to beb(¹ P ₁, 173)=605(20) MHz.     

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.     

Calculation of the hyperfine structure of the 42 S 1/2, 42 P 1/2, 42 P 3/2 states in the 3d 10 nl configuration of Cu

The hyperfine structure of the 4² S _1/2, 4² P _1/2, 4² P _3/2 states in the 3d ¹⁰ nl configuration of Cu has been evaluated using many-body perturbation theory. Polarisation effects were included in all orders and correlation to third-order. By the use of iteration methods, a large number of higher order diagrams were also included. The correlation effects between the valence electron and the 3d shell were found to be very important. The results forA(² S _1/2) andA(² P _1/2) 5827MHz and 440 MHz, respectively, are in good agreement with the experimental results, whereas the result forA(² P _3/2)=83 MHz is far from the experimental value. No explanation was found for the discrepancy. The quadrupole values were found to be ?206 mb for⁶³Cu and ?185 mb for⁶⁵Cu.     

Bestimmung derP 3/2 —D 3/2-Aufspaltimg und Nachweis von crossing-Signalen im Zustandn=3 von ionisiertem Helium

Radio frequency induced transitions between 3D _5/2- and 3P _3/2-Zeeman sublevels in He⁺ have been detected. From the position of the line center of theD _5/2 (m=?1/2)—P _3/2(m=1/2) transition, the splittings 3D _5/2—3P _3/2=(17259±13) MHz and 3P _3/2—3D _3/2=(81±13) MHz have been deduced. The theoretical values are 17254.9 and 85.4 MHz. Three crossings of Zeeman sublevels of the 3S-, 3P- and 3D-states of He⁺ have been detected both by a magnetic and an electric field modulation method. The crossing-field strengths are in good agreement with the calculated values.     

Fine and hyperfine structure of the 22 P term of7Li; determination of the nuclear quadrupole moment

Microwave transitions between the Zeeman split doublet states 2² P _1/2 and 2² P _3/2 of⁷Li have been measured using the optical double resonance method. The fine structure separation was determined to bev _fs=10.053.184(58) MHz. The hyperfine structure was well resolved and led to considerably improved precision of the diagonal coupling constantsa _1/2=45.914(25) MHz,a _3/2=?3.055(14) MHz,b=?0.221(29) MHz. Furthermore, the contact, spin dipolar and orbital magnetic hyperfine constants are evaluated using additional results from level crossing experiments, which are more sensitive on the non-diagonal magnetic hyperfine constanta _3/2,1/2. The results are in good agreement with recent theoretical calculations. The nuclear quadrupole moment is derived fromb to beQ(⁷Li)=?41(6) mbarn.     

Isotope shift and hyperfine structure of the transition5d6s 2 2 D 3/2-5d6s6p 4 F 3/2 of Lu175 and Lu176

Using a tunable single mode dye laser the isotope shift of the 573.7 nm-line between the isotopes Lu¹⁷⁵ and Lu¹⁷⁶ has been determined to be IS(176?175, 573.7 nm)=?394(5) MHz yielding a change of mean square nuclear radii ofδ〈r ²〉=0.022(5) fm². In addition from our measurements the following values of the hyperfine splitting constantsA andB could be deduced Lu¹⁷⁶ 5d6s6p ⁴ F _3/2:A=?651.4(0.3) MHz,B=2,494(4) MHz 5d6s ^{2 2} D _3/2:A=138.0(0.3) MHz,B=2,131(3) MHz Lu¹⁷⁵ 5d6s6p ⁴ F _3/2:A=?924.7(0.5) MHz,B=1,767(4) MHz.     

Hyperfine structure of the 4s4p1P1-state of67Zn by level crossing spectroscopy

The magnetic dipole coupling constantA of the 4s 4p¹P₁ state of⁶⁷Zn was measured in a level crossing experiment. The result is A(4s4p¹P₁ ⁶⁷Zn)= 17.7(5) MHz. In a modified Breit-Wills theory thisA factor leads to a parameter λ_P= 0.71(3), which describes the difference in the radial wave functions of thep-electron in 4s4p¹P₁ and³P₁ states respectively. The lifetime of the 4s4p¹P₁ state was remeasured by Hanle-effect experiments. The result τ=1.41± 0.04 nsec is in good agreement with other measurements.     

Investigation of hyperfine structure and isotope shift of the 605.5 nm-line of Lu176 by laser spectroscopy

Using a tunable single mode dye laser the hyperfine structure of the transition 5d6s ^{2 2} D _5/2 — 5d6s6p ⁴ F _5/2 has been investigated for the Lu-isotopes Lu¹⁷⁵ and Lu¹⁷⁶. From our measurements the following values for the hyperfine constantsA andB could be deduced Lu¹⁷⁶ 5d6s6p ⁴ F _5/2:A=698.4 (0.4) MHz,B=1,564 (10) MHz 5d6s ^{2 2} D _5/2:A=104.1 (0.3) MHz.B=2,631 (6) MHz Lu¹⁷⁵ 5d6s6p ⁴ F ^5/2:A=987.2(0.4) MHz,B=1,117(6) MHz. The isotope shift between the line centers has been determined to be IS(176-175, 605.5 nm)=?420(10) MHz.     

Atomic beam magnetic resonance investigations in the 2p 2 3 P ground multiplet of the stable carbon isotopes12C and13C

The hyperfine structure seperations Δv andg _J -factors have been measured in the 2p ^{2 3} P states of¹³C(I=1/2) and¹²C(I=0), respectively, using the atomic beam magnetic resonance method. The results are Δv(³ P ₁,¹³C)=4.200 (25) MHz, Δv(³ P ₂,¹³C)=372.593 (25) MHz,g _J (³ P ₁,¹²C)=1.501052 (13), andg _J (³ P ₂,¹²C)=1.501039 (15). After applying corrections due to perturbations by neighbouring fine structure levels one deduces the constants of the magnetic dipole interactionA(³ P ₁,¹³C)=+2.838 (17) MHz, A(³ P ₂,¹³C)=+149.055 (10) MHz. No signs of theA-factors were determined by the experiment; they follow from the known positive sign of the nuclear magnetic moment μ _I of¹³C. CombiningA(³ P ₂,¹³C) with the results of other measurements on¹¹C, yields μ _I (¹¹C)=?0.964 (1) nm.     

Measurement of the fine structure separation in the 42 D term of lithium by the method of electric field induced level anti-crossing

An electric field is employed to convert lithium 4² D Zeeman level crossings into anti-crossings. The lithium atoms are excited by electron impact. The anti-crossings are detected by the change in polarization of the light emitted in the 4² D-2² P transition. From the corresponding values of the magnetic field, we obtain 400 (10) MHz for the zero field fine structure energy separationE(4² D _5/2)-E(4² D _3/2).     

Core polarization of the133Cs atom by the 7p electron

The hfs of the 7² P _1/2 state of Cs has been measured by optical double resonance yieldingA(7² P _1/2,¹³³Cs)=94.35 (4) MHz. The core polarization contribution to the hfs and the value 〈r ^?3〉 _j =2.54 · 10⁺²⁴ cm^?3 of the 7p electron of Cs has been calculated from the experimental data and was compared with current theories indicating still an appreciable uncertainty in the atomic wave functions of this one-electron atom.     

High resolution spectroscopy of prompt and metastable decaying levels in highly ionized argon,especially of the metastable3 P 2-state of Ar16+ and the4 P 5/2-state of Ar15+

Besides the prompt x-ray emission of Ar-ions, the metastable decay of the heliumlike³ P ₂- and the lithiumlike⁴ P _5/2-levels of highly ionized Ar¹⁶⁺ and Ar¹⁵⁺ atoms has been observed in a foil-excited beam using a flat-crystal spectrometer. Due to the highx-ray energy resolution of the spectrometer the two³ P ₂ →¹ S ₀ and⁴ P _5/2 →² S _1/2 transitions could be resolved. The experiment yielded (3128 ±2) eV for the³P₂ → and (3091 ± 2)eV for the⁴ P _5/2 →² S _1/2 transition energy respectively. Using a time of flight technique the lifetimes of the³ P ₂- and the⁴ P _5/2-states were determined to be (1.44 ±0.09)ns and (0.66 ± 0.05) ns.     

Determination of the isotope shift of115m Cd by a Zeeman scanning method

We have used an optical pumping-Zeeman scanning technique in order to determine the isotope shift in the 3,261 Å resonance line of 43-day, spin-11/2^115m Cd. A sample of ≈5×10¹² atoms was aligned in the¹ S ₀ diamagnetic ground state by optically pumping the sample with one selected Zeeman-scanned component of the³ P ₁?3,261 Å resonance line from a¹¹⁴Cd lamp. The alignment was detected through the modulation of the pumping beam at the nuclear resonance frequency. Thus by Zeeman scanning theF = 9/2 component of the³ P ₁ level and using previously determinedA- andB-values, we findδ5v(114–115m (9/2))= ?4,234(48) MHz and¹¹⁴Cd-^115mCd isotope shift = 87(48) MHz. We calculate a staggering parameterγ(^115mCd)=0.73(26), and a change in mean-square nuclear charge radiusδ〈r ²〉^114,115m =0.035(18)fm².     

Magnetic moment of the 5/2−1/2[541] ground state of 14h 185Ir

The magnetic and electric hyperfine splitting frequencies ¦gμ _N B _HF/h¦ ande ² qQ/h of the 5/2^?1/2[541] ground state of 14h ¹⁸⁵Ir in Ni were measured with nuclear magnetic resonance on oriented nuclei to be 360.8(7) MHz and +6.7(2.0) MHz, respectively. The ground state magnetic dipole moment and electric quadrupole moment of¹⁸⁵Ir are deduced to be ¦μ¦=2.601 (14)μ _N andQ=?1.9(5)b, taking values for the hyperfine field and electric field gradient of B_HF=?454.9 (2.3) kG and eq=?0.151(4) × 10¹⁷ V/cm², respectively. The negative quadrupole moment is in agreement with nuclear-orientation data and proves again theI ^π K=5/2^? 1/2 ground state configuration.     

Measurement of the population of the4 P 5/2-state in Ar15+ by cascading processes

The population of the⁴ P _5/2-state in Ar¹⁵⁺-ions by cascading processes was measured. The corrected lifetime is (0.55±0.04) ns and is in very good agreement with the theoretical value of 0.56 ns. At a specific beam energy of 1.4 MeV/u the lifetime of the³ P ₂-state of Ar¹⁶⁺ is not influenced by cascading processes and is (1.44±0.08) ns. The energies of the³ P ₂ →¹ S ₀- and⁴ P _5/2 →² S _1/2-transitions are (3127.2±0.5) and (3090.0±0.7) eV, respectively.     

Pressure broadening and collisional shift of the Rb D2 absorption line by CH4, C2H6, C3H8, n-C4H10, and He

The pressure broadening and shift rates of the rubidium D2 absorption line 5²S_1/2→5²P_3/2 (780.24 nm) with CH₄, C₂H₆, C₃H₈, n-C₄H₁₀, and He were measured for pressures ≤80 Torr using high-resolution laser spectroscopy. The broadening rates γ_B for CH₄, C₂H₆, C₃H₈, n-C₄H₁₀, and He are 28.0, 28.1, 30.5, 31.3, and 20.3 (MHz/Torr), respectively. The corresponding shift rates γ_S are −8.4, −8.8, −9.7, −10.0, and 0.39 (MHz/Torr), respectively. The measured rates of Rb for the hydrocarbon buffer gas series of this study are also compared to the theoretically calculated rates of a purely attractive van der Waals difference potential. Good agreement is found to exist between measured and theoretical rates.     

Hyperfeinstrukturaufspaltung und Lebensdauer des 72 P 3/2-Terms von Rb85 und Rb87

The hyperfine structure splitting of the 7² P _3/2 state of Rb⁸⁵ and Rb⁸⁷ has been measured with optical double resonance. The following hfs interaction constants have been obtained: Rb⁸⁵:A _7p ⁸⁵ =3.71(1) MHz;B _7p ⁸⁵ =3.68 (8)MHz. Rb⁸⁷:A _7p ⁸⁷ =12.57(1) MHz;B _7p ⁸⁷ =1.71 (3)MHz. These values yield quadrupole moments ofQ _7p,hfs ⁸⁵ =+0.316(7) barn andQ _7p,hfs ⁸⁷ =+0.147(2)barn which are reduced by application of the Sternheimer correction toQ _7p ⁸⁵ =+0.267(6) barn andQ _7p ⁸⁷ =+0.124(2) barn. The averaged ratio of the uncorrected values of Q_hfs in the 5p and 7p ² P _3/2 stake isQ _5p,hfs/Q _7p,hfs=1.07(3). This has to be compared with the correction factors for polarization of the core of electrons by the nuclear quadrupole moment (1?R)_5p/(1?R)_7p=1.07. The agreement between the measured and calculated ratio indicates a net antishielding of the nuclear quadrupole moments of rubidium by the core of electrons as has been predicted bySternheimer. The lifetime of the 7² P _3/2 state of the RbI-spectrum is:τ(7² P _3/2, Rb)=2.4(2)·10^?7 sec.     

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.