Hyperfine Structure Measurements Research Articles

Measurement of hyperfine structure in Pr II by collinear laser-ion-beam spectroscopy

Measurement of hyperfine structure in Pr II by collinear laser-ion-beam spectroscopy

PILIS: Post-ISOCELE Laser Isobar Separation — a high efficiency apparatus for laser spectroscopy

A new experimental setup PILIS II has been installed on line with the ISOCELE isotope separator (IPN, Orsay). The mass-separated ions are slowed from 30 kV to 500 V and implanted on a graphite collecting disk. The atoms are then thermally desorbed at the implantation region by Nd-YAG laser pulses and selectively ionised by three laser beams. The ions created are mass identified by a time-of-flight (TOF) system. Two versions of the TOP system with accelerating voltage of 1.5 and 30 kV were used to carry out hyperfine structure measurements. With the 30 kV system we obtained an overall detection efficiency of 8.4 × 10 −5. First measurements were performed on very light gold isotopes. It has been shown that PILIS II is well adapted to study very short half-life isotopes ( T 1 2 ∼ 1 s ).

Nuclear charge radii changes of uranium and hafnium isotopes determined by laser spectroscopy

The present work reports measurements of isotope shifts and hyperfine structure in the optical spectra of two high-Z elements: Hf and U. The experiments are based on the observation of the resonance fluorescence in a well collimated atomic beam, excited by a tunable dye laser. The chains of the stable Hf isotopes and of233–236, 238U have been investigated and changes in ms nuclear charge radii have been deduced. The results have been discussed from the point of view of nuclear structure in the investigated regions.

Detection of the quadrupole hyperfine structure in HCNH(+)

We report the first measurement of the electric quadrupole hyperfine structure of HCNH(+). The J = 1-0 transition of this interstellar molecular ion was observed toward the cold, dark cloud TMC-1, using the NRAO 12 m telescope at 74 GHz. The three hyperfine components of this transition were clearly detected and resolved, enabling the first experimental determination of the quadrupole coupling constant eqQ of HCNH(+). The value of this constant is calculated to be eqQ = -0.49 +/- 0.07 MHz. The column density of HCNH(+) toward TMC-1 was found to be N(tot) about 2.8 x 10 exp 13/sq cm, corresponding to a fractional abundance relative to H2 of f about 3 x 10 exp -9. This abundance is at least one order of magnitude higher than the predictions of ion-molecule chemistry. Detection of the hyperfine structure clearly establishes the presence of HCNH(+) in interstellar space.

PILIS: post-ISOCELE laser isobar separation; a high efficiency apparatus for laser spectroscopy

A new experimental setup PILIS II has been installed on-line with the ISOCELE isotope separator (IPN, Orsay). The mass-separated ions are slowed from 30 kV to 500 V and implanted on a graphite collecting disk. The atoms are then thermally desorbed at the implantation region by Nd: YAG laser pulses and selectively ionized by three laser beams. The ions created are mass identified by a time-of-flight (TOF) system. Two versions of the TOF system with accelerating voltages of 1.5 and 30 kV were used to carry out hyperfine structure measurements. With the 30 kV system we obtained an overall detection efficiency of 1.4 × 10 −5. First measurements were performed on very light gold and platinum isotopes. It has been shown that PILIS II is well adapted to study very short half-life isotopes ( T 1 2 ∼ 1 s ).

An ion trap for nuclear laser spectroscopy at Tohoku ISOL

An on-line ion trap directly connected to the Tohoku ISOL has been constructed. The trap is aimed at the study of nuclear magnetic properties through precision measurements of ionic ground-state hyperfine structures of unstable nuclei. As a first step to a systematic study, the hyperfine splitting of the ground state of 87Sr + ions was measured by laser microwave double-resonance spectroscopy.

Hyperfine-structure measurements on trapped Pb II.

The 6${\mathit{P}}_{3/2}$-6${\mathit{P}}_{1/2}$ magnetic dipole resonance transition in ${\mathrm{Pb}}^{+}$ has been observed by cw laser excitation of an ion cloud stored in a Paul trap and subsequent detection of the fluorescence radiation. From the hyperfine-structure splitting of the spectrum we determine the A factor for the ground state, A(${\mathit{P}}_{1/2}$)=12.967(13) GHz, and the excited state, A(${\mathit{P}}_{3/2}$)=0.580(3) GHz. From a contamination of $^{208}\mathrm{Pb}$ in our sample we derived the $^{207}\mathrm{Pb}^{+}$${\mathrm{\ensuremath{-}}}^{208}$${\mathrm{Pb}}^{+}$ isotope shift [\ensuremath{\Delta}\ensuremath{\nu}=311(14) MHz]. A small electric quadrupole admixture giving rise to a \ensuremath{\Delta}F=2 component in the spectrum has been determined to be 6.4(0.5)% of the total transition amplitude.

Spin uncoupling in 3A2 CS2 studied by high-resolution Zeeman and hyperfine quantum beat spectroscopy

The magnetic properties of the evsB2 spin component of the 3A2 state in the molecule CS2 have been investigated with a resolution of ∼100 kHz by quantum beat spectroscopy in a supersonic jet. Zeeman-level tuning in 12CS2 and 13CS2, providing Landé g factors, and measurements of the 13CS2 nuclear hyperfine structure were carried out, particularly to investigate their J dependence. Based on these results, it is proposed that both the magnetic moment and the hyperfine splitting are dominated by spin-uncoupling interactions, described in the rotational Hamiltonian by B(J−S).2 In addition, the g factors and rotational state lifetimes were used to provide spectroscopic assignments and to elucidate details of the state mixing.

Hyperfine structure measurements in the IF B-X system

Hyperfine structure measurements in the IF B-X system

Hyperfine structure measurements of 151,153Eu II with fast ion beam-laser spectroscopy

Hyperfine structure measurements of the levels 4f 7 ( 8S 0 7 2 )5d 9D 0 5,6 and 4f 7( 8S 0 7 2 )6p 3 2 ; J=5 in 151,153Eu II have been performed with collinear fast ion beam-laser spectroscopy. The hyperfine coupling constants A and B are evaluated.

J off-diagonal effects in the hyperfine-structure splitting in the Eu I term e6D of 4f76s6d.

In the analysis of high-resolution Doppler-free two-photon hyperfine-structure (hfs) measurements of levels in the Eu i term $^{6}\mathrm{D}$ of the configuration 4${\mathit{f}}^{7}$6s6d of $^{151}\mathrm{Eu}$ and $^{153}\mathrm{Eu}$ the necessity occurs to take into account also hfs perturbations. For the magnetic hfs interactions of $^{151}\mathrm{Eu}$, the following off-diagonal matrix elements $^{151}$${\mathit{A}}_{1}$(JJ') could be determined from the high-resolved two-photon line profiles: $^{151}$${\mathit{A}}_{1}$(1/2,3/2)=5.70(3) GHz, $^{151}$${\mathit{A}}_{1}$(3/2,5/2)=4.3(2) GHz, $^{151}$${\mathit{A}}_{1}$(5/2,7/2)=2.9(2) GHz, $^{151}$${\mathit{A}}_{1}$(7/2,9/2)=2.2(2) GHz. The high quality of the calculations is represented both in the reproducibility of the absolute hfs level energies and also in the hfs anomaly where a mean value deduced from the corrected magnetic hfs constants of -0.66(8)% can be stated.

Laser spectroscopic hyperfine structure measurements of 51V as a test of a new parametrization of the hyperfine structure

The hyperfine structure (HFS) of the four high lying and metastable fine structure levels of vanadium-51 have been calculated. The calculations are based on the parametrization of one- and two-body interactions to the second order perturbation theory for a model space of the three configurations 3d 3+ M 4s M ( M = 0, 1, 2). The experimental HFS data were measured using the laser spectroscopic double-resonance technique (ABMR-LIRF) with high-frequency precision.

Hyperfine structure measurements of 235U High-Lying Levels Using a Hollow-Cathode Lamp

The hyperfine structure (hfs) of three 235U high-lying levels has been measured by using a hollow-cathode lamp and laser-induced fluorescence technique. These transitions are from the first excited states at 16900 and 16505 cm-1 to the higher excited states. From the measured spectra, the isotope shifts and hfs widths for these levels are determined, and the hfs constants A and B for two levels are obtained.

Measurement of Hyperfine Structure of the 4f35d5G-4f36p5Hin PrII by Collinear Laser-Ion-Beam Spectroscopy

The hyperfine structure of the transitions 4 f 3 ( 4 I o )5 d 5 G 2 o -4 f 3 ( 4 I o )6 p 5 H 3 (λ=601.94 nm) and 4 f 3 ( 4 I o )5 d 5 G 3 o -4 f 3 (^4I^o)6 p ^5H_3 (λ=604.83 n m ) o f P r I I h a s b e e n m e a s u r e d b y c o l l i n e a r l a s e r - i o n - b e a m s p e c t r o s c o p y . T h e m a g n e t i c - d i p o l e c o n s t a n t A a n d t h e e l e c t r i c - q u a d r u p o l e c o n s t a n t B o f t h e l e v e l s i n v o l v e d h a v e b e e n d e t e r m i n e d t o b e : A ( M H z ) B ( M H z ) 4f^3(^4I^o)5 d ^5G_2^o 1703.2±0.8 -14.1±5.8 4f^3(^4I^o)5 d ^5G_3^o 932.8±2.2 -15.1±6.6 4f^3(^4I^o)6 p ^5H_3 1028.7±1.0 -14.3±2.5.

Sternheimer free determination of the47Ti nuclear quadrupole moment from hyperfine structure measurements

Sternheimer free determination of the47Ti nuclear quadrupole moment from hyperfine structure measurements

Laser-induced fluorescence and microwave-optical double resonance spectra of the iodine chloride (A .rarw. X, 19 .rarw. 0) vibronic band: measurement of the chlorine atom hyperfine structure

Fluorescence excitation spectra of the A, {sup 3}II{sub 1} {l arrow} X, {sup 1}{Sigma}{sup +} electronic transition of I{sup 35}Cl have been obtained by using a single-frequency dye laser and a collimated molecular beam. The 5-MHz resolution of the spectra is sufficient to resolve the Cl atom hyperfine structure of the A, {sup 3}II{sub 1}, state for the first time. The values obtained for the I atom hyperfine constants also are improved. Assignments of the highly structured spectra were confirmed by microwave-optical double resonance using previously assigned microwave transition in the X, {sup 1}{Sigma}{sup +}, ground electronic state. Unlike the hyperfine constants of the X and B, {sup 3}II{sub 0} states, those of the A state differ markedly from the predictions of simple models based on molecular orbital descriptions of the electronic structure. This data will provide a very sensitive test of quantum calculations for the excited electronic state.

Sternheimer free determination of the51V nuclear quadrupole moment from hyperfine structure measurements

The hyperfine structure (hfs) of 18 metastable states of51V has been measured by laser induced fluorescence. 15 of these states have been measured additionally very precisely by the ABMR-LIRF method. Using results of earlier hfs measurements, the hfs of altogether 33 fine structure states is analyzed using a method of simultaneous parametrization of one- and two-body interactions in the atomic hfs of the model space 3d3 +M 4s2 −M (M = 0, 1, 2). The hfs of these states is described by 16 parameters for the magnetic dipole interaction and 12 parameters for the electric quadrupole interaction. From these model space parameters corresponding configuration dependent parameters for the three configurations were determined. These parameters allow a prediction of the hfs constants of all states of the modelspace within an accuracy of 5 to 10%. The evaluation of the nuclear quadrupole moment of51V, free of Sternheimer corrections up to second order, yielded the value of -0.043(5) barn.

Hyperfine structures in 167Er II: Measurements of high 4f125d levels and ab initio multiconfiguration Dirac-Fock calculations.

Hyperfine-structure measurements in high 4${f}^{12}$5d metastable levels of $^{167}\phantom{\rule{0ex}{0ex}}\mathrm{i}\mathrm{i}$ have been carried out to supplement earlier data on the low 4${f}^{12}$6s levels. Ab initio multiconfiguration Dirac-Fock (MCDF) calculations have been performed, and the effects of core excitations and configuration interaction have been investigated. While good agreement between experiment and calculation was found for the low 6s levels, a less clear interpretation emerges from the higher 6d levels. This points directly to the problems in the MCDF scheme in understanding the effects of core excitation and configuration interaction.

Precision spectroscopy on stored, highly charged ions using free-electron-laser radiation

The feasibility of a precision measurement of the ground-state hyperfine structure of hydrogenlike sodium is considered, based on the use of a proposed rf-linac extreme-UV free-electron laser. The laser would be used for intensity-pumping population redistribution within the ground-state sublevels of the stored ions, through excitation of the 1s–2p transition near 1 nm. The magnetic dipole transition between the hyperfine-structure sublevels would be detected by changes in the mean number of scattered 1.2-keV photons following the low-frequency transition.

High-precision measurements of hyperfine structure in Tm II, N 2+ and Sc II

We have applied the technique of collinear fast-ion-beam laser spectroscopy to measure the hyperfine structure (hfs) in Sc II, Tm II and N 2 +. Laser-induced fluorescence was observed from a 50 keV ion beam which was superimposed with the output of an actively stabilized ring dye laser (rms bandwidth < 1 MHz). Hyperfine measurements were made in the metastable 3d 2 and the excited 3d4p configuration of Sc II and in the 4f 136s and 4f 135d configurations of Tm II. The fine and hyperfine structure of N 2 + has been observed in the (0, 1) and (1, 2) bands of B 2 Σ u + −X 2 Σ g + system. Higher-resolution measurements of the metastable 3d 2 configuration in Sc II were also made by laser-rf double resonance. The experimental results are compared with those obtained by multiconfiguration Dirac-Fock ab-initio calculations.