Collinear Laser Ion Beam Spectroscopy Research Articles

Studies of Land\xe9 gJ-factors of singly ionized neodymium isotopes (142, 143 and 145) at relatively small magnetic fields up to 334 G by collinear laser ion beam spectroscopy

The Zeeman splitting at moderate magnetic fields (up to 334 G) of 20 lines of Nd II,covering the part 569.89 nm to 617.05 nm of the visible spectral range were investigated.We used a Doppler-free collinear laser ion beam spectroscopy technique supported by aprecise computer analysis. From the Zeeman effect studies we re-investigated the LandégJ factors for 20 odd levels between 22 850and 30 002 cm-1 and11 evenlevels lying between 6005 and 12 460 cm-1. We compared our data with other availableexperimental and theoretical values. We achieved an accuracy better than that of otherauthors, making our data valuable for future theoretical parametric studies.Graphical abstract

Revised Landé gJ-factors of some 141Pr II levels using collinear laser ion beam spectroscopy

The Zeeman effect of singly ionized praseodymium spectral lines was studied at small magnetic fields up to 334G, using the high-resolution spectroscopic method of collinear laser-ion-beam spectroscopy (CLIBS), where a collimated fast ion beam is superimposed with a counter propagating laser beam tuned to the desired transition. This nearly Doppler-effect-free technique enables to observe linewidths as low as 100MHz and thus to record the Zeeman patterns of the hyperfine structure of the investigated spectral lines.From the Zeeman patterns of 21 lines of Pr II lines in the range 570.45–609.038nm we have re-determined the Landé gJ-factors of 14 levels of the f3dodd and 16 levels of the f3p and f2d2even configurations.The obtained experimental Landé factors are compared with available earlier measurements as well as with theoretical calculations.

Investigations of the Zeeman effect of some 142Nd ionic levels, using collinear laser ion beam spectroscopy

By performing laser excitation from the even 4f45d lower levels to the odd 4f46p and 4f35d2 upper levels of the neodymium ion 142Nd+, we have observed Zeeman splitting in an external magnetic field up to 330G. We applied the high resolution spectroscopic method of collinear laser ion beam spectroscopy (CLIBS). With this method (unconventional for studying the Zeeman effect) we recorded very well-resolved Zeeman structure patterns with line widths of order of 100MHz, which is only sometimes the natural line width. The obtained experimental Landé factors are compared with earlier measurements and with theoretical calculations.

Investigation of the hyperfine structure of 143Nd+ spectral lines using collinear laser ion beam spectroscopy

The high resolution technique of collinear laser ion beam spectroscopy is used to determine the hyperfine structure constants of 6 metastable even-parity levels (E < 10 000 cm−1) and 19 odd-parity levels (E < 27 000 cm−1) of 143Nd+. The magnetic dipole interaction constants A and the electric quadrupole interaction constants B were determined with high accuracy. For six levels the hyperfine interaction constants were measured for the first time.

Zeeman effect of hyperfine-resolved spectral lines of singly ionized praseodymium using collinear laser–ion-beam spectroscopy

Using the high-resolution spectroscopic method of collinear laser--ion-beam spectroscopy (CLIBS), the Zeeman effect of singly ionized praseodymium spectral lines has been studied at relatively small magnetic fields up to 330 G. With this unusual method for studying the Zeeman effect of ionic lines we recorded Zeeman-hyperfine structure patterns with clearly resolved components with linewidths as low as 60 MHz, which is only sometimes the natural linewidth. From the Zeeman patterns of 30 lines, improved Land\'e ${g}_{J}$ factors were determined for 39 Pr ii levels of the $4{f}^{3}5d$, $4{f}^{2}5{d}^{2}$, and $4{f}^{3}6p$ configurations.

A study of hyperfine transitions of singly ionized praseodymium (141Pr+) using collinear laser ion beam spectroscopy

54 spectral lines of singly ionized praseodymium (141Pr+) have been investigated using the high resolution spectroscopic method of collinear laser ion beam spectroscopy (CLIBS). Magnetic dipole interaction constants A and electric quadrupole interaction constants B of 49 involved levels could be determined. 19 levels are investigated for the first time using this technique. The A-values could be determined with uncertainties less than 1 MHz.

Hyperfine structure investigations and identification of new energy levels in the ionic spectrum of 147Pm

Hyperfine structure splittings have been measured for 75 lines of singly ionized promethium 147Pm II with a hollow cathode discharge and a Fabry-Perot interferometer. Magnetic dipole and electric quadrupole splitting factors A and B have been determined for 10 levels of the 4f56s configuration, 2 levels of 4f55d, and 57 upper undesignated levels. The A-factors are in general agreement with calculated values. With the aid of Hartree-Fock calculations and Zeeman-effect data, four new levels of the 4f5(6H)5d 7K term were located. The strong lines terminating on these 7K levels originate from levels of 4f5(6H)6p7I, which were already known, but had not been designated. An unidentified line at 556.17 nm previously observed with collinear laser ion-beam spectroscopy is now classified as 4f5(6H)5d7K6-4f5(6H)6P7I5.

J-dependence of optical isotope shifts in Sm II

Isotope shift measurements in 18 optical transitions between 8 samarium isotopes ASm have been taken (A=144, 146, 147, 148, 149, 150, 152, 154) using collinear laser ion beam spectroscopy. For the even-A isotopes, a direct-measurement technique was developed. A multidimensional King plot served to evaluate the term-related isotope shifts in the fine-structure multiplet 4f6(7F)5d8HJ. These shifts should show a linear dependence on J(J+1) in accordance with a crossed second-order approximation. A closer correlation is found between the isotope shifts and the fine-structure energies. Field shift and mass shift can be separated in order to calculate changes of mean-square charge radii delta (r2).

Excited-level lifetimes and hyperfine-structure measurements on ions using collinear laser-ion-beam spectroscopy.

The mean lifetimes \ensuremath{\tau} of the Ca ii 4p $^{2}$${\mathit{P}}_{1/2}$ and 4p $^{2}$${\mathit{P}}_{3/2}$ levels, and the $^{35}\mathrm{Cl}$ ii 4p' $^{1}$${\mathit{F}}_{3}$ level, have been measured by a variant of the collinear laser--ion-beam lifetime technique applied previously to the Ar ii 4p' $^{2}$${\mathit{F}}_{7/2}^{\mathit{o}}$ level [Jian Jin and D. A. Church, Phys. Rev. A 47, 132 (1993)]. The present results are \ensuremath{\tau}(Ca ii, 4p $^{2}$${\mathit{P}}_{1/2}$)=7.098(0.020) ns, \ensuremath{\tau}(Ca ii, 4p $^{2}$${\mathit{P}}_{3/2}$)=6.924(0.019) ns, and \ensuremath{\tau}(Cl ii, 4p' $^{1}$${\mathit{F}}_{3}$) =11.17(0.06) ns. The experimental lifetimes of these, plus the Ar ii 4p' $^{2}$${\mathit{F}}_{7/2}$ level, are compared with available recent many-electron calculations. Typically 1%--3% differences between measurement and ab initio theory are found, while certain semiempirical calculations are in better agreement with experiment. Data for other precise lifetime measurements on alkali-metal systems are compared with recent ab initio and semiempirical calculations to provide perspective on the Ca II results. The hyperfine structure of the $^{35}\mathrm{Cl}$ II 3d' $^{1}$${\mathit{G}}_{4}$--4p' $^{1}$${\mathit{F}}_{3}$ transition was also measured and analyzed in the course of the measurements, with the resulting hyperfine-structure constants: A${(}^{1}$${\mathit{F}}_{3}$)=301.9(0.5) MHz, B${(}^{1}$${\mathit{F}}_{3}$)=-6.7(0.8) MHz, A${(}^{1}$${\mathit{G}}_{4}$)=205.1(0.5) MHz, and B${(}^{1}$${\mathit{G}}_{4}$)=-3.9(2.4) MHz.

How accurate are the "muonic" quadrupole moments in Eu?

The electric quadrupole hyperfine structure splitting constants B of the Eu isotopes 145-147, 151-153 were measured with collinear laser ion beam spectroscopy in 17 different transitions. From 105 experimental data B values of all levels in EuII 4f 7 ( 8 S)5d 9 D J ,...6p(7/2;1/2) J , and...6p(7/2;3/2) J were determined in enhanced accuracy. The ratio 151 B/ 153 B=0.39184(22) (mean value) significantly deviates from values of muonic measurements but is in good agreement with other atomic ones in Eu I and Eu II

Hyperfine structure and isotope shift investigations of 145Pm and 147Pm

In the promethium II spectrum hyperfine structures (HFS) and isotope shifts (IS) of the two transitions 4f 5(6H)5d 7KJ=4 to 23261.30J=3 cm-1 at lambda =557.6 nm and 4f 5(6H)5d 7KJ=4 to 23761.98J=3 cm-1 at lambda =542.5 nm of the radioactive isotopes 145Pm and 147Pm have been studied by collinear laser ion beam spectroscopy. The nuclear moments for 145Pm have been deduced. A hyperfine structure anomaly could not be detected. The sign of the isotope shift confirms the 5d-6p character of the transition. The experimental data for the moments are in relatively good agreement with Hartree-Fock and Nilsson model calculations and with that of neighbouring nuclei of europium and praseodymium.

Collinear laser ion beam spectroscopy

Collinear Laser Ion Beam Spectroscopy (CLIBS) investigates hyperfine structures (hfs) and isotope shifts (IS) in spectral lines and is well suited for the study of nuclear moments of short-lived isotopes. It is fast, highly selective, highly sensitive and allows many experimental alternatives. The high accuracy makes it also an interesting tool for atomic physics.

A simple and effective stabilization system for collinear laser ion-beam spectroscopy at mass separators

In principle, Collinear Laser Ion-Beam Spectroscopy (CLIBS) needs very efficient stabilization of the laser frequency ν and the ion energy U to obtain high resolution. The requirements on the stabilization of ν and particularly on U are reduced by a differential measuring technique, using a second beam of stable isotopes as a reference. The ions are kept in resonance with ν by monitoring the fluorescence light. The stabilization may act on the ion energy by a post-acceleration system or on ν. The time constant (1 to 0.05 s) depends on the intensity of the reference beam. Instabilities of ν and U with longer time constants do not affect the measurements. As a main advantage this technique is independent of the separator regime and avoids a highly sophisticated stabilization of U. Therefore, we could use our system unaltered at two different mass separators.

Experiences with collinear laser spectroscopy of ion beams from electromagnetic isotope separators

Collinear Laser Ion-Beam Spectroscopy (CLIBS) needs some special precautions with regard to the regime and construction of the electromagnetic isotope separator in order to achieve the high precision and sensitivity possible with this method. Collinearity of the laser and ion beam can be obtained by a well-designed ion optical system and is influenced by the angular dispersion of ions. The knowledge of the kinetic energy of the ions is very important; it depends on the acceleration voltage and the voltage drops in the ion source, the flight tank, and the interaction chamber. The sensitivity depends for instance on the population of the investigated atomic states and is influenced by the ion-source characteristics, by de-excitation during flight and by laser pumping. An increase of sensitivity by further development of this technique is anticipated.

Investigations of europium isotopes with neutron numbers between 84 and 93 by collinear laser ion-beam spectroscopy

Hyperfine structures and isotope shifts of the transition Eu II 4f7(8S72/O)6p3/2 (7/2,3/2)4 — 4f7 (8S72/O)5d9D4O,λ=6O4.95 nm, of the radioactive isotopes147, 149, 155, 156Eu have been studied by collinear laser-ion beam spectroscopy (CLIBS). The nuclear moments and the differences of the mean square nuclear charge radii as well as the deformation parameters have been deduced. The experimental data for the odd-A nuclei are in a good agreement with simple Nilsson model calculations.

Collinear laser-ion beam determination of hfs in Cs II

By making use of the “velocity bunching” effect in collinear laser-ion beam spectroscopy, the hfs of the 5 p 5 2 P 3 2 5 d[ 3 2 ] 0 2→ 2 P 3 2 6 p[ 3 2 ] 2 transition in Cs II has been determined. A 30% reduction in linewidth compared with measurements using perpendicular laser-ion beam geometry is observed. The results for the 6 p[ 3 2 ] 2 level are compared with semi-empirical calculations.