Atomic-beam Laser Spectroscopy Research Articles

J dependences of the isotope shift and hyperfine structure in the Sm I 4f65d6s 9H term.

Isotope shifts and hyperfine structures of twelve transitions from the high-lying metastable $^{9}$${\mathit{H}}_{\mathit{J}}$ (J=1--7) states of the 4${\mathit{f}}^{6}$5d6s configuration in Sm i have been measured for the stable isotopes by means of atomic-beam laser spectroscopy. Hyperfine constants A and B for the odd-mass isotopes $^{147}\mathrm{Sm}$ and $^{149}\mathrm{Sm}$ are determined for the $^{9}$${\mathit{H}}_{\mathit{J}}$ (J=1--7) states and six upper levels of the transitions in Sm i. $J--- dependences of the isotope shifts are observed for the 4${\mathit{f}}^{6}$5d6s $^{9}$H term. Parameters ${\mathit{z}}_{5\mathit{d}}$ of the crossed-second-order effect are derived for the 4${\mathit{f}}^{6}$5d6s configuration, and ${\mathit{z}}_{5\mathit{d}}$/\ensuremath{\lambda} is found to be 165(10) MHz/${\mathrm{fm}}^{2}$. It has been verified that the field shift is dominant in the crossed-second-order effect.

Isotope shift and hyperfine structure in Lu I and W I.

Isotope shifts and hyperfine structures of four transitions in W i have been measured as well as isotope shifts in Lu i by means of atomic-beam laser spectroscopy. Magnetic-dipole hyperfine constants A of $^{183}\mathrm{W}$ are determined for the atomic states $^{7}$${\mathit{D}}_{1}$, $^{7}$${\mathit{F}}_{1}$, and $^{7}$${\mathit{F}}_{3}$ of the 5${\mathit{d}}^{4}$6s6p configuration. The nuclear parameters \ensuremath{\lambda} and \ensuremath{\delta}〈${\mathit{r}}^{2}$〉 are derived for W stable isotopes. J dependences of the isotope shifts are observed for the $^{2}$D term of the 5d6${\mathit{s}}^{2}$ configuration in Lu i and the $^{5}$D term of the 5${\mathit{d}}^{4}$6${\mathit{s}}^{2}$ configuration in W i. Parameters ${\mathit{z}}_{5\mathit{d}}$ of the crossed-second-order effects are derived for the Lu i 5d6${\mathit{s}}^{2}$ and W i 5${\mathit{d}}^{4}$6${\mathit{s}}^{2}$ configurations, and ${\mathit{z}}_{5\mathit{d}}$/\ensuremath{\lambda} is found to be 411(26) MHz/${\mathrm{fm}}^{2}$ for W. A systematic behavior of the normalized parameter ${\mathit{z}}_{\mathit{n}\mathit{l}}$/\ensuremath{\lambda}${\mathrm{\ensuremath{\zeta}}}_{\mathit{n}\mathit{l}}$ is discussed.

Hyperfine structures and level isotope shifts of then 2 S 1/2 (n=7 ? 12)- andn 2 D 3/2,5/2 (n=6 ? 10)-levels of203,205Tl measured by atomic beam spectroscopy

Applying atomic beam laser spectroscopy, hyperfine constants as well as level isotope shifts of the (6s2ns)2S1/2 levels (n = 7 – 12) and (6s2nd)2D3/2,5/2 levels (n = 6 – 10) have been measured in203Tl and205Tl. Furthermore, some new hyperfine constants and level isotope shifts of the Tl2P1/2,3/2-states are presented together with corrected results of earlier experiments. The hyperfine splittings have been compared with the predictions of the semiempirical theory. For theD-states a relatively poor agreement between these theoretical predictions and experimental results has been found. Using the experimental level isotope shifts and the δ〈r2〉 value from muonic X-ray data, results of single-configuration Dirac-Fock calculations have been tested.

Systematic study of isotope shifts and hyperfine structures in YbI by atomic-beam laser spectroscopy

Systematic study of isotope shifts and hyperfine structures in YbI by atomic-beam laser spectroscopy

Direct observation of the Delta J=2 forbidden transition in Nd I induced by the second-order hyperfine perturbation.

The fluorescence of a forbidden transition from the ground state ${(}^{5}$I, J''=4) to the 18 249.275-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ (J=6) level in Nd i was directly observed by atomic-beam laser spectroscopy. This transition was found to be caused by the second-order hyperfine perturbation from the close-lying 18 249.784-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ (J'=5) level. Thus the fluorescence peaks were observed only for odd isotopes of $^{143}\mathrm{Nd}$ and $^{145}\mathrm{Nd}$, and no peaks for even isotopes. Both the relative frequencies and the relative intensities of all the observed forbidden transitions agree well with the theoretical calculation.

Systematic Study of Isotope Shiftsand Hyperfine Structures in YbIby Atomic-Beam Laser Spectroscopy

Isotope shifts of 9 transitions from the ground and metastable states in Yb I were measured for 7 stable isotopes with A =168-176 by means of atomic-beam laser spectroscopy. Hyperfine constants A and B of 12 levels for 171 Yb and 173 Yb were determined. Reliable values of nuclear parameters λ were obtained and changes in mean square nuclear charge radii δ< r 2 > were deduced using both the two-parameter model and the numerical calculation. Deformations for Yb stable isotopes were discussed. Hyperfine constants A and B were analyzed with the effective operator procedure and the single-electron hyperfine parameters of 6 s and 6 d electrons were derived for the Yb I 4 f 14 6 s 6 d configuration. For the 3 D J and 1 D 2 states of 4 f 14 6 s 6 d , J and term dependences of isotope shifts were obtained and the parameters of the crossed-second-order effect were derived to be z 6 d /λ=18(6) MHz/fm 2 and g 2 (6 s , 6 d )/λ=-1120(60) MHz/fm 2 .

Isotope shifts and hyperfine structure in polonium isotopes by atomic-beam laser spectroscopy.

Atomic electrons can be used to probe nuclei by studying details of atomic spectra: the isotope shift of spectral lines contains information on the change of the mean square charge radius from one isotope to another one, while the hyperfine splitting allows to determine spins and the lower electromagnetic moments of nuclei.

Hyperfine Structure and Isotope Shift in Er I by the Atomic-Beam Laser Spectroscopy

Isotope shifts of 5 transitions from the 3 H 6 and 3 F 4 levels of the ground configuration 4 f 12 6 s 2 in Er I were measured for the stable isotopes with A =162-170 by the atomic-beam laser spectroscopy. Hyperfine constants A and B of 7 atomic levels were determined. Changes of mean square nuclear charge radii δ and mean square nuclear deformation parameters δ were deduced. The deformations of 164-170 Er were found to be mainly quadrupole and contributions of higher order deformation parameters for 162 Er were estimated. J -dependence of isotope shifts in the (6, 1) term of 4 f 12 6 s 6 p was found. It is concluded that the J -dependence was caused by the crossed-second-order effect in which the field shift has dominant contribution.

Changes of the Nuclear Charge Distribution of Nd, Sm, Gd and Dy from Optical Isotope Shifts

Isotope shifts and hyperfine structures in 28 optical transitions for 28 stable isotopes of Nd, Sm, Gd and Dy were measured by means of the atomic-beam laser-spectroscopy. The nuclear parameter λ was obtained from the isotope shift measurement for all the stable nuclei with the improved accuracy. The λ values were analyzed by using the Fermi distribution for the nuclear charge density. As a result, the diffuseness at the nuclear surface or the hollow depth near the center of nucleus in the charge distribution depends on the neutron number. The values of δ and also δ were determined. It is shown that λ is a good probe into the systematic change of the nuclear charge distribution.

J dependences of the isotope shift and hyperfine structure in Gd I 4f75d6s2 9D, 4f75d6s6p 9D, and 9F terms.

Isotope shifts of 16 transitions in 4${\mathit{f}}^{7}$5d6${\mathit{s}}^{2}$${(}^{9}$D)-4${\mathit{f}}^{7}$5d6s6p${(}^{9}$D${,}^{9}$F) of Gd i for the stable isotopes with A=152--160 were measured by atomic-beam laser spectroscopy. The hyperfine constants A and B of $^{155}\mathrm{Gd}$ and $^{157}\mathrm{Gd}$ in two $^{9}$D terms and the $^{9}$F term were determined. The single-electron hyperfine parameters ${\mathit{a}}_{4\mathit{f}}^{10}$ for the 4f electron and ${\mathit{a}}_{5\mathit{d}\mathit{s}}^{\mathit{k}}$${\mathit{k}}_{\mathit{l}}$,${\mathit{b}}_{5\mathit{d}\mathit{s}}^{\mathit{k}}$${\mathit{k}}_{\mathit{l}}$ for the 5d electron were deduced. The electric quadrupole moments Q of $^{155}\mathrm{Gd}$ and $^{157}\mathrm{Gd}$ were obtained to be 1.27(5)b and 1.36(6)b, respectively. The J dependences of the isotope shifts in two $^{9}$D terms and the $^{9}$F term were observed. The parameter ${\mathit{z}}_{5\mathit{d}}$ of the crossed-second-order effect for the $^{9}$D term of 4${\mathit{f}}^{7}$5d6${\mathit{s}}^{2}$ was derived, and the value of ${\mathit{z}}_{5\mathit{d}}$/\ensuremath{\lambda} was obtained to be 134(4) MHz/${\mathrm{fm}}^{2}$. We confirmed that the field shift is dominant in the crossed-second-order effect and the specific mass shift is negligible.

A test of the accuracy of atomic-beam laser spectroscopy

To determine the accuracy to which hyperfine splittings can be measured using a cw dye laser with rf sideband tuning, a series of atomic beam experiments with59Co was performed. One hyperfine splitting of the first excited metastable atomic state was measured and compared with the results for the same splitting from magnetic rf resonance experiments. The uncertainty with the methods applied was found to be about 0.05 to 1% of the experimental linewidth in general; it is ±20 kHz or ±0.05% of the linewidth in the present Co experiment. The hyperfine splitting constants of the 3d 8 4p 2 F 7/2 state were found to beA=419.3(9) MHz,B=−77(17) MHz.

Larmor precession measurement of the nuclear g1factor of135,137Ba isotopes in a fat atomic beam

An original method of determining the nuclear Lande factor for atoms with a diamagnetic ground state is illustrated with the two odd-A isotopes 135Ba and 137Ba. The method, based on the fast atomic beam laser spectroscopy technique, consists of detecting the in-flight Larmor precession of the nuclear magnetic dipolar moment in a static magnetic field, via the fluorescence induced by resonant laser light. When the magnetic-field amplitude is varied the fluorescence signal exhibits a fringed structure from which the g1 factor can be deduced.

Experimental studies of high-lying Rydberg states in atomic rubidium

This paper summarizes a long series of experiments that have been done on Rydberg states of Rb. The basic experimental technique that has been used is atomic-beam laser spectroscopy which allows both low-resolution and high-resolution studies. Excitation of Rydberg states is provided by single-photon absorption from a suitably frequency-doubled rhodamine $6G$ tunable laser. Detection is done by field ionization and ion counting. These techniques have allowed us to study the critical ionizing field, which has been found to follow classical, hydrogenic behavior closely. Rydberg states of Rb have been observed from $n=28$ up to $n&gt;100$. High-resolution spectroscopic studies have led to measurement of the fine structure for $\mathrm{np}$ levels located between $n=28$ and $n=60$, as well as the isotope shift of the ground state, $\ensuremath{\delta}\ensuremath{\nu}=(172\ifmmode\pm\else\textpm\fi{}15)$ MHz. Anomalies in the intensity ratio of the doublet $5s\ensuremath{-}np$ transitions have been observed and interpreted as relativistic effects. Perturbations by weak and strong dc electric field are reported. In the case of weak electric fields it is possible to evaluate the polarizability. In the case of strong dc electric fields, new phenomena have been observed and analyzed. We also find experimental evidence of selective photoionization in the presence of an appropriate dc electric field, which could have some applications in laser isotope separation. Finally, we give the preliminary results of an experiment on the effect of a strong nonresonant electromagnetic field on high-lying Rydberg states.

Spins, magnetic moments, and isotope shifts ofNa21−31by high resolution laser spectroscopy of the atomicD1line

A polyisotopic sodium beam produced by reactions of 20 GeV protons in an uranium target, was illuminated with a tunable cw dye laser. The atomic beam is analyzed by a six-pole magnet, ionized, and detected after selection of one isotope by use of a mass spectrometer. From the optical ${D}_{1}$ resonance lines the hyperfine structure, magnetic moments, and isotope shifts of $^{21\ensuremath{-}31}\mathrm{Na}$ have been determined. The nuclear spins of $^{26\ensuremath{-}30}\mathrm{Na}$ have been measured by magnetic resonance. The results are discussed in terms of nuclear deformation. The analysis of isotope shifts shows the presence of an appreciable volume shift contribution.NUCLEAR STRUCTURE $^{26\ensuremath{-}30}\mathrm{Na}$; measured $J$. $^{21\ensuremath{-}31}\mathrm{Na}$; measured isotope shifts; deduced $\ensuremath{\mu}$. Atomic beam laser spectroscopy and magnetic resonance.