Measurements of hyperfine structure and shift for atomic uranium by laser induced-fluorescence spectroscopy

The paper reports that the isotope shift between natural uranium isotope 235and 238 and the hyperfine sturcture width width of U~(235) were measured by means of laser-in-duced fluorescence spectroscopy.The A and B hyperfine structure splitting constants of U~(235)were also given for 14643 cm~(-1),15720 cm~(-1)and 15631 cm~(-1) levels.     

Isotope shift and hyperfine structure of43Ca by laser spectroscopy

The isotope shift⁴⁰Ca-⁴³Ca in the 4s ^{2 1} S ₀-4s4p ³ P ₁ intercombination line as well as the hyperfine structure splitting of the 4s4p ³ P ₁ state of⁴³Ca have been remeasured by saturation spectroscopy with a tunable stabilizedcw dye laser and an atomic beam of natural Ca as absorber. The nuclear charge radius of⁴³Ca obtained here reconciles our result with the radius obtained from measurements in muonic Ca-atoms and in the Ca resonance line. It reconfirms the fact that the charge radius of⁴³Ca is considerably smaller than the ones of both neighbouring even isotopes. The discrepancy of our previous measurement for this charge radius was due to a wrong assignment of so far unobserved absorption lines of probably molecular origin occuring in the neighbourhood of the atomic resonances under study.     

Application of the laser ion source for isotope shift and hyperfine structure investigation

The study of nuclei far from stability requires high sensitivity of the experimental technique. The method of Resonance Ionization Spectroscopy in a Laser Ion Source (RIS/LIS) allows one to carry out measurements of the isotope shifts and hyperfine splittings for isotopes at the production rate about 10² atoms per second. The sensitivity of this method is determined by the high efficiency of the laser ion source and the low background of the detection system afforded by characteristic α particle registration. The isotope shifts and hyperfine structures of ¹⁵⁵Yb, ¹⁵⁴Tm (I=9 and I=2) and ¹⁵³Tm (I=11/2) have been measured and the isotopic changes in mean square charge radii and nuclear electromagnetic moments have been determined. The further development of this experimental method – enhanced Target Ion Source system aimed to suppress thermionic background – enables direct detection of the photoions and widens the range of the applicability of the RIS/LIS method. This revised version was published online in August 2006 with corrections to the Cover Date.     

Rubidium isotope shifts and hyperfine structure by two-photon spectroscopy with a multi-mode laser

The technique of two-photon laser spectroscopy without Doppler broadening is applied to atomic rubidium vapor. The hyperfine splitting and isotope shifts of several highly excited states are measured. We demonstrate the suitability of a tunable laser source oscillating simultaneously in many longitudinal modes for two-photon spectroscopy.     

Hyperfine structure and isotope shift studies of rhenium by laser optogalvanic spectroscopy

Doppler-limited high resolution laser optogalvanic spectra of six transitions of rhenium lying in the range 560–620 nm have been recorded. Isotope shifts between the two natural isotopes of rhenium,¹⁸⁵Re and¹⁸⁷Re, have been calculated in all the six transitions. Hyperfine coupling constants for eight levels belonging to the configurations 5d ⁵6s ², 5d ⁶6s, 5d ⁴6s ²6p and 5d ⁵6s6p are reported. Wherever possible our constants are compared with those given by others.     

Topics in atomic hyperfine structure and isotope shift

Recent developments in atomic hyperfine structure and isotope shift are discussed under the following aspects: (i) Precise evaluation of nuclear moments and isotopic change of nuclear charge radii by quantitative computation of atomic structure or by calibration of the atomic constants through results from electronic and mesic X-ray spectroscopy. (ii) How to apply spectroscopic methods to nuclei far off stability. (iii) What can be learned from a systematic investigation of long isotopic chains.     

Lamb shift, fine structure and hyperfine structure in helium like ions by fast beam laser spectroscopy

Using Doppler tuned fast beam laser spectroscopy with a continuous wave CO₂ laser the following energy intervals in helium like ions have been measured: 1s2s ¹S₀–1s2p ³P^1,F, ³P₀ in ^14,15N⁵⁺; 1s2p ³P_2,F–1s2p ³P_1,F' in ¹⁹F⁷⁺; and 1s2p ³P₀–1s2p ³P₁ in ²⁴Mg¹⁰⁺. The results test modern relativistic and QED atomic theory. This revised version was published online in August 2006 with corrections to the Cover Date.     

Measurement of isotope shift and hyperfine splitting of190, 191, 193, 197Pb isotopes by collinear laser spectroscopy

We report here on the measurement of isotope shift and hyperfine splitting of^{190, 191, 193, 197}Pb for the 723 nm atomic optical transition. Detailed analysis of the optical data has been done by combining them with the available muonic and electronicx-ray isotope shift data. The magnetic dipole moments and the electric quadrupole moments of the odd isotopes have been extracted from the hyperfine coupling constants of the atomic states involved in the optical transition used.     

Refined MCHF evaluations of field isotope shift and hyperfine structure in the calcium atom

In the calcium atom, the MCHF method has been applied for evaluating the field-shift electronic parts of both 4s ²-4s4p lines, and the hyperfine-structure electronic effective parameters of the 4s4p ³ P ₂ and¹ P ₁ levels. For the hyperfine structures, the far-configuration mixing corrections have been computed with the assumption that the lower state is itself a two-componentsp+dp state in close-configuration mixing.     

Frequency measurement, isotope shift and hyperfine structure of the transition in atomic silver

The frequency of the centroid of the transition in Ag I has been determined by laser spectroscopy of a collimated metastable thermal atomic beam. We find MHz. The isotope shift MHz. For the magnetic hyperfine structure constant of the state, assuming IJ coupling, we find, MHz and MHz. Received 16 July 1999 and Received in final form 7 October 1999     

Isotope shift and hyperfine structure measurements for 155Yb by laser ion source technique

The change in the mean square charge radius and electromagnetic moments of the neutron deficient ¹⁵⁵Yb isotope have been determined using resonance ionization spectroscopy in a laser ion source. The data point to an absence of a marked deformation change for Yb isotopes with N=84−86. Received: 2 October 1997 / Revised version: 24 October 1997     

Determination of the isotope shift of 190Hg by on-line laser spectroscopy

By use of a pulsed tunable dye laser the isotope shift of $\text{(T}\text{1}\text{2}\text{= 20 min)}$¹⁹⁰Hg in the $\text{6s}{}^2{}^1\text{S}{}_0\text{?6s6p}{}^3\text{P}{}_1$, λ = 2537 Å line has been measured at the on-line mass separator ISOLDE/CERN. The preliminary result relative to ²⁰⁴Hg is $\text{IS}{}^{\mathrm{<mtext>204</mtext><mtext>190</mtext>}}\text{= 31.8(3) GHz}$.     

Isotope shifts and hyperfine structure of 38–47K by laser spectroscopy

Laser optical spectroscopy on a thermal atomic beam has been performed on the $\text{4}{}^2\text{S}{}_{\mathrm{<mtext>sol1</mtext><mtext>2</mtext>}}\text{?4}{}^2\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{D}{}_2$ line of ^{38,39,41–47}K. Hyperfine structure constants and isotope shifts have been measured. Magnetic moments and changes in the mean square charge radii are deduced.     

High resolution dye laser spectrometer for measurements of isotope and isomer shifts and hyperfine structure

A high resolution cw dye laser spectrometer with a frequency calibration system of 100 kHz resolution is described. Two examples of measured isotope shifts will be discussed.     

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.     

Finestructure, hyperfine structure and isotope shift of 4f 6s7s in Er I

The isotope shift (IS) and hyperfine structure (hfs) of nine levels (31720 to 38921 cm^-1) assigned to the configuration 4 f ¹² 6 s 7 s in neutral erbium have been determined experimentally using Doppler-reduced saturation absorption spectroscopy in a gas discharge. We performed a fine structure analysis in the SL-coupling scheme of the single configuration 4 f ¹² 6 s 7 s, confirming and extending the classification of even parity Er I levels. We discriminated the different hfs contributions of the 4f¹² core and the (6 s +7 s) outer electrons of the shell in a non-relativistic JJ-coupling approach and in the relativistic effective tensor operator formalism in SL-coupling. The relativistic one-electron parameters of the hfs for ¹⁶⁷Er were fitted to the experimental data by a least squares fit procedure: [0pt] a ⁰¹ _4f =-147(3) MHz, [0pt] a ¹⁰ _6s + a ¹⁰ _7s =-1840(30) MHz, [0pt] b ⁰² _4f =6560(80) MHz. The level dependencies of the isotope shift were evaluated based on crossed second order (CSO) effects. We obtained the following results for the CSO parameters for the isotope pairs ^170-168Er: d _6s7s =-740(30) MHz, z _4f = 0(5) MHz, ( g _3,6s ( f , 6 s )+ g _{3, 7s} ( f , 7 s ))= -24(15) MHz and for ^170-166Er: d _6s7s =-1500(50) MHz, z _4f =0(10) MHz, ( g _3,6s ( f ,6 s )+ g _3,7s ( f +7 s ))=-50(29) MHz. The resulting parameters for the hfs are compared with those known for other configurations of the Er atom and ion. Received 16 May 1999 and Received in final form 31 January 2000     

High-resolution LIF measurements on hyperfine structure and isotope shifts in various states of Lu I using the second and third harmonic of a cw Ti:sapphire laser

With the second and third harmonic of a tunable single-mode cw Ti:S laser, generated inside external enhancement cavities, high-resolution LIF measurements on several states of Lu I in various parts of the electromagnetic spectrum are performed. From these measurements, hyperfine structure A and B constants for both ¹⁷⁵Lu and ¹⁷⁶Lu as well as isotope shifts have been determined for all levels observed in the single-step excitation process. From the measured A constants, the magnetic hyperfine structure anomaly has been derived for various states. Received 14 January 2002 Published online 19 July 2002