Lifetimes of the 4s4p 3 P 1 and 4s3d 1 D 2 states of Ca I

The lifetimes of the 4s4p ³ P ₁ and 4s3d ¹ D ₂ metastable states of Ca have been studied using the time-of-flight technique. Two kinds of observations were performed. First, the exponential decay of the fluorescence, using a (continuous) dc discharge for excitation and then the velocity distribution of the radiating atoms, using a pulsed discharge, were measured. From the combined results of these measurements the lifetimes were derived. The lifetimes of the 4s4p ³ P ₁ and 4s3d ¹ D ₂ states of Ca are determined to be 0.57±0.03 ms and 1.5±0.4 ms, respectively.     

Lifetime measurements of the 3d 94s(1 D) 4p configuration of Cu I

The radiative lifetimes of the levels in the 3d ⁹4s(¹ D)4p configuration of Cu I are measured. The levels are excited from the metastable 3d ⁹4s ^{2 2} D _3/2,5/2 levels. The metastable Cu atoms are generated in a pulsed hollow cathode discharge. The levels investigated are populated with a 35-ps laser pulse at wavelengths around 220 nm. The laser induced fluorescence signal is detected. The lifetime of the 3d ⁹4s(³ D)4p ⁴ D _1/2 level is also determined by direct excitation from the ground state. A comparison with calculated literature values is given.     

Hyperfinestructure-investigations in the mangan I configurations 3d 5 4s 4p and 4s 5s

Nine transitions (ranging from 475 till 733 nm) between the excited configuration 3d ⁵ 4s 5s and 3d ⁵ 4s 4p of⁵⁵Mn were investigated with computer supported interference spectroscopy. Thus the hyperfine structure (hfs) of the four 4s 5s and the twelve 4s 4p levels is now completely known from experiment. The hfs results are discussed with the effective operator technique and for 4s 4p the accuracy of the one-electron parametersa ^ik could be improved:a _3d ¹⁰ =?6.28(24),a _4s ¹⁰ =154.0(1.4),a _4p ⁰¹ =9.3(8),a _4p ¹² =7.7(2.5) in mK. For the configuration 4s 5s — for which fine structure calculations are not yet available — the experimental hfs data prove a practically pureS-character. Besides the one-electron splitting parameters deduced:a _3d ¹⁰ =?6.5(5),a _4s ¹⁰ =182(3),a _5s ¹⁰ =24(3) in mK, permit to determine the degree of mixing between the twoe ⁶ S _5/2 andf ⁶ S _5/2 levels which amounts to about 3%.     

Hyperfine structure studies in the mixed configurations (4p 2 4d+4s 4p 4) of arsenic

The magnetic hyperfine structures of some levels of the 4p ² 4d configuration which mixes strongly with the 4s 4p ⁴ configuration, have been measured for the first time, using the Fabry-Perot technique in the far UV range. A good agreement is observed between experimental results and theoretical evaluations.     

J-dependence of the isotope shift in Gd I 4f 75d6s 2(a 9 D)

The angular distribution of electrons resulting from off-resonant ionisation of atomic hydrogen has been measured recently [1]. Here we report calculations of these angular distributions using the method of implicit summation [2] to calculate the n-photon absorption probabilities in the nth order of perturbation theory.     

Tensor polarizabilities of the 4f 7(8 S)5d6s 2 9 D 2,3,4,5,6 levels in Gd I

The optical pumping method with rf detection and the nonlinear level crossing technique were used in parallel electric and magnetic fields to investigate the Stark splitting of all the fine structure levels of the ground multiplet 4f ⁷ (⁸ S) 5d6s ^{2 9} D in Gd I. The tensor polarizabilities were deduced from the level crossing and the rf signals. The variation of the tensor polarizabilities is well reproduced by the LS coupling approximation, except for the small value of the⁹ D ₅ level. A value of the tensor polarizability of the 5d electron is evaluated from the experimental results, ₂(5d)=2.00(6) kHz(kV/cm)². It is shown that the ratio between the electric quadrupole constant and the tensor polarizability is constant, except for the⁹ D ₅ ratio, which is caused by a breakdown of the central field model.     

Fine structure and hyperfine structure in the excited configuration 5p 26s of the antimony I spectrum

By optical interference and VUV spectroscopy the doublet system of SbI 5p ²6s was investigated, so that now the hyperfinestructure of all 8 levels of 5p ²6s (A- andB-splitting constants) are known. From the analysis we receive a spin-orbit parameter ζ_5p =3,538(57) cm^?1 and from the hyperfine-analysis single electron splitting constantsa _5p ⁰¹ =52.4(4.6),a _5p ¹⁰ =?1.6(7.3),a _5p ¹² =72.3(2.3),a _6s ¹⁰ =91.7(4.1),b _5p ⁰² =?49.6(1.1) andb _5p ¹¹ =30.4(3.2) (all values in mK). For all calculations in the fs- and hfs-analysis the 5p ²6s ² D _3/2 has to be excluded (see discussion). With the figures given above the quadrupole moment¹²¹ Q(5p ²6s)=?0.44(3) barn was obtained. It is in good agreement with the¹²¹ Q(5p ³). For the core-polarization by the 5p electron in the innerfieldns-shells (n=1, 2, 3, 4, 5) and the unpaired 6s electron a field of +500(300) kG was obtained.     

Magnetic hyperfine structure in the 4p 3 and 4p 25s configurations of arsenic

The magnetic hyperfine structure factorA of the quasi-totality of the levels of the low 4p ³ and 4p ²5s configurations of As I has been measured by Fabry-Perot interferometry in the far UV range. A good agreement is observed between experimental results and theoretical evaluations, which allows us to confirm that the 4p ²5^s configuration only mixes very weakly (less than 1%) with 4s4p ⁴.     

J-dependence of the isotope shift in Eu I 4f 75d6s(a 6 D)

The J-dependence of the isotope shift (IS) in the term a⁶D of the Eu I configuration 4f⁷5d6s was determined to be: z_5d(⁶D)=+34.5(1.5) MHz. This proves that in the phenomenological interpretation of the IS distinct parameters z_nl(^mL) for the J-dependence in one term are necessary.     

Ab initio structure of 3p4p in Si I

Multiconfiguration calculations have been performed in order to estimate ab initio energies for the configuration 3p4p in Si I. A preliminary attempt has also been made to calculate E2 transition rates for transitions from levels of 3p ² to those of 3p4p. However, these rates show a gauge dependence, which indicates that further correlation needs to be included to obtain accurate rates and lifetimes.     

Experimental and theoretical study of the hyperfine structure in the (5d+6s)96p configurations of Pt I

The hyperfine structure of the odd configurations 5d ⁹6p and 5d ⁸6s6p was studied with laser optogalvanic spectroscopy and high resolution interferometry in a platinum hollow cathode. A parametric hyperfine structure analysis for the configurations (5d+6s)⁹6p with 10 excited odd-parity levels was performed for¹⁹⁵Pt. We obtained one-electron hfs parameters,a _5d ⁰¹ =1160(320) MHz,a _6s ¹⁰ =35600(5300) MHz anda _6p ⁰¹ =1300(780) MHz for the configuration 5d ⁸6s6p. The corresponding $\left\langle {r^{ - 3} } \right\rangle _{nl}^{k_s k_l } $ values are compared with those known for other 5d-elements.     

Crystal structure of the copper(I) complex Cu(py-Clan)(PPh3)I

Journal of Structural Chemistry - A mixed ligand copper(I) Schiff base complex [Cu(py-Clan)(PPh3)I], where py-Clan = = 4-chlorophenylpyridine-2-ylmethyleneamine, is synthesized and structurally...     

Hyperfine structure in 5s 4d 3 D —5snf transitions of87Sr

The hyperfine spectra of the 5s4d ³ D ₁-5s20f, 5s4d ³ D ₂-5s23f, and 5s 4d ³ D ₃-5s32f transitions of⁸⁷Sr (I=9/2) have been measured by collinear fast beam laser spectroscopy. The structure in the upper configurations is highly perturbed by fine structure splitting that is of comparable size to the hyperfine interaction energy. These perturbations can be adequately treated with conventional matrix diagonalization methods, using the 5s-electron magnetic dipole interaction terma _5s and the unperturbed fine structure splittings as input parameters. Additionally, hyperfine constants for the lower 5s4d ³ D configurations, including theA- andB-factors and a separation of the individuals- andd-electron contributions to these factors, are derived.     

Hyperfine structure in the configurations4f 4 6s 2 and4f 4 5d 6s of Nd I

The high resolution laser-atomic-beam technique was used to investigate the hyperfine structure in Nd I 4f ⁴6s ^{2 5} I,⁵ F,⁵ S and 4f ⁴5d6s ⁷ L,⁷ K,⁷ I,⁷ H. The metastable states were populated by an arc discharge burning in the atomic beam. The measured hyperfine constantsA andB of the levels of 4f ⁴6s ² and 4f ⁴5d6s allow a parametric analysis to be performed using the effective tensor operator formalism. The experimental radial integrals of the 4f and 5d electrons fit with those of the other lanthanides. The 4f radial integrals are in agreement with values of optimized Hartree-Fock-Slater calculations. The spectroscopic quadrupole moments of¹⁴³Nd and¹⁴⁵Nd are deduced from the 4f parameters:Q _I =?0.610(21) b and ?0.314(12) b, respectively. TheQ _I resulting from the 5d parameter are in satisfactory agreement with these values. The hyperfine anomaly due to thes electron in 4f ⁴5d 6s amounts to about 1%.     

Wavelength and isotopic shift measurements of the3S(3s 4s) −3P(3s 3p) MgI transitions

The wavelengths of the³S(3s 4s) ?³P(3s 3p) MgI transitions have been measured for the²⁴Mg isotope with a precision of ±2 × 10^?7; moreover the isotope shifts of the above transitions have been measured for the three natural Mg isotopes as well as the hyperfine constants of the³S(3s 4s) level of²⁵Mg. The measurements have been performed in a metastable atomic beam.     

Oscillator strengths of Pd I 4d5s–4d5p by branching fraction measurement

Oscillator strengths for 16 lines of Pd I from 4d⁹5s–4d⁹5p transitions have been derived by combining the adopted lifetimes with the data of branching fractions measured in this work based on the emission spectrum of a hollow cathode lamp. The results have some significant differences compared with the reported in the literature. Among them the results of 13 lines improves the reported data. New results obtained in this paper are useful for more accurate spectra analysis concerning Pd atom.     

Hyperfine structure and core polarization in Nd I 4f 4f 4 5d6s

The high resolution laser-atomic-beam technique was used to investigate the hyperfine structure in Nd I 4f ⁴ 5d6s ⁷ L, ⁷ K, ⁷ I, ⁷ H, ⁷ G, ⁵ L, ⁵ K, and ⁵ I for both of the stable odd isotopes. The metastable states were populated by an arc discharge burning in the atomic beam, and 31 transitions to higher odd levels have been studied. Knowledge of the hyperfine constants of 34 levels of 4f ⁴ 5d6s allowed a comprehensive parametric analysis to be performed, using the effective tensor operator formalism. Compared to earlier analyses, a significant reduction of errors has been achieved for all the parameters. The contact parameter a _4f ¹⁰ has been fitted freely, thus providing an experimental value for the core-polarization effects. They are about six times larger than the relativistic effects.     

Hyperfine structure in the configurations 4f 13 6s6p and 4f 125d6s 2 of TmI

The laser-atomic-beam spectroscopy has been used to make precise measurements of the hyperfine structure in transitions starting from metastable states of the configuration 4f ¹²5d6s ² in¹⁶⁹TmI. With the resulting experimental magnetic dipole hyperfine constantsA _J andA _J values from former investigations a parametric analysis of the hyperfine structure in the configurations 4f ¹³6s6p and 4f ¹²5d6s ² has been performed using wavefunctions from fine structure calculations. A comparison of theoretical and experimental hyperfine constants allowed a test of the reliability of the wave-functions used. The hyperfine parameters respectively hyperfine radial integrals determined from the analysis were compared with corresponding data from ab initio calculations for the ground configuration in TmI.     

Hyperfine structure in the configuration 4f 115d6s 2 of Er I

Hyperfine constants of low lying levels of the configuration 4f ¹¹5d6s ² in Er I have been measured for the only stable odd isotope,¹⁶⁷Er, using high resolution laseratomic-beam spectroscopy. Hyperfine parameters were evaluated from the experimental data using the effective tensor operator formalism. For this purpose eigenfunctions have been determined from an analysis of the fine structure energies of Er I as well as from ab initio multiconfiguration Dirac-Fock calculations. With the latter method also ab initio hyperfine constants for the levels investigated were evaluated. A comparison of calculated fine structure energies, Landég _J -factors and hyperfine constants with the experimental data allowed a test of the reliability of the fine structure and multiconfiguration Dirac-Fock wavefunctions. Effective nuclear electric quadrupole moments for¹⁶⁷Er have been determined from the experimental hyperfine constants using both calculated relativistic electronic radial integrals and hyperfine parameters for the 4f and 5d electrons in the configuration 4f ¹¹5d6s ² in Er I. From a comparison with the nuclear quadrupole moment measured in the mesic atom Sternheimer shielding factors are calculated. Configuration-interaction contributions to the radial integrals 〈r ^?3〉 _nl ⁰¹ of the 4f and 5d electrons have been determined.