The series Lecture Notes in Chemistry (LNC), reports new developments in chemistry and molecular science quickly and informally, but with a high quality and the explicit aim to summarize and communicate current knowledge for teaching and training purposes. Books published in this series are conceived as bridging material between advanced graduate textbooks and the forefront of research. They will serve the following purposes:  • provide an accessible introduction to the field to postgraduate students and nonspecialist researchers from related areas, • provide a source of advanced teaching material for specialized seminars, courses and schools, and • be readily accessible in print and online. The series covers all established fields of chemistry such as analytical chemistry, organic chemistry, inorganic chemistry, physical chemistry including electrochemistry, theoretical and computational chemistry, industrial chemistry, and catalysis. It is also a particularly suitable forum for volumes addressing the interfaces of chemistry with other disciplines, such as biology, medicine, physics, engineering, materials science including polymer and nanoscience, or earth and environmental science.  Both authored and edited volumes will be considered for publication. Edited volumes should however consist of a very limited number of contributions only. Proceedings will not be considered for LNC.  The year 2010 marks the relaunch of LNC.

Lecture notes in Chemistry

Atomic polarization phenomena impinge upon a number of areas and processes in physics. The dielectric constant and refractive index of any gas are examples of macroscopic properties that are largely determined by the dipole polarizability. When it comes to microscopic phenomena, the existence of alkaline-earth anions and the recently discovered ability of positrons to bind to many atoms are predominantly due to the polarization interaction. An imperfect knowledge of atomic polarizabilities is presently looming as the largest source of uncertainty in the new generation of optical frequency standards. Accurate polarizabilities for the group I and II atoms and ions of the periodic table have recently become available by a variety of techniques. These include refined many-body perturbation theory and coupled-cluster calculations sometimes combined with precise experimental data for selected transitions, microwave spectroscopy of Rydberg atoms and ions, refractive index measurements in microwave cavities, ab initio calculations of atomic structures using explicitly correlated wavefunctions, interferometry with atom beams and velocity changes of laser cooled atoms induced by an electric field. This review examines existing theoretical methods of determining atomic and ionic polarizabilities, and discusses their relevance to various applications with particular emphasis on cold-atom physics and the metrology of atomic frequency standards.

https://iopscience.iop.org/article/10.1088/0953-4075/43/20/202001/pdf

Theory and applications of atomic and ionic polarizabilities

SEVERAL recent experimental findings1–3 have pointed to a possible route for making an X-ray laser, which could in principle provide an imaging system capable of molecular resolution4. The method involves the multiphoton excitation of atoms in van der Waals clusters or in molecules to yield ions with core-electron vacancies1,2, which can then decay by emission of X-rays, in conjunction with a self-chanelling propagation mode of electromagnetic radiation3. The multiphoton excitation may be stimulated by ultrahigh-brightness, subpicosecond pulses of laser light5. We have previously observed2 emission of X-rays from L-shell transitions in core-excited krypton atoms using this approach. Here we report the multiphoton production of X-rays of wavelength 2–3 A from highly ionized xenon atoms which possess a large number of innershell vacancies while retaining several electrons in relatively weakly bound outer orbitals. Atoms with this ‘inverted’ electronic configuration are designated ‘hollow atoms’6,7. We find that generation of hollow atoms can become the dominant excitation mode for such systems, making their exploitation in an X-ray laser a real possibility.

Multiphoton-induced X-ray emission at 4-5 keV from Xe atoms with multiple core vacancies

Interaction of slow multicharged ions with solid surfaces

We give an overview of the work done with the Laboratoire National de Metrologie et d'Essais-Systemes de Reference Temps-Espace (LNE-SYRTE) fountain ensemble during the last five years. After a description of the clock ensemble, comprising three fountains, FO1, FO2, and FOM, and the newest developments, we review recent studies of several systematic frequency shifts. This includes the distributed cavity phase shift, which we evaluate for the FO1 and FOM fountains, applying the techniques of our recent work on FO2. We also report calculations of the microwave lensing frequency shift for the three fountains, review the status of the blackbody radiation shift, and summarize recent experimental work to control microwave leakage and spurious phase perturbations. We give current accuracy budgets. We also describe several applications in time and frequency metrology: fountain comparisons, calibrations of the international atomic time, secondary representation of the SI second based on the 87Rb hyperfine frequency, absolute measurements of optical frequencies, tests of the T2L2 satellite laser link, and review fundamental physics applications of the LNE-SYRTE fountain ensemble. Finally, we give a summary of the tests of the PHARAO cold atom space clock performed using the FOM transportable fountain.

/pdf/progress-in-atomic-fountains-at-lne-syrte-4iv0bboiab.pdf

Progress in atomic fountains at LNE-SYRTE

The perturbation method for calculating atomic energies by power series in 1/Z and αZ has been extended to include parameters for screening and for expansion in the principal quantum number n. Numerical results are given and compared with observations for 1s nl and 1s2 nl of the helium and lithium isoelectronic sequences.

Energy Levels of He- and Li-Like Ions (States 1snl, 1 s2nl with n = 2-5)

The x-ray emission following the impact of highly charged Xe[sup [ital q]+] ([ital q]=44--48) ions of 7-keV/[ital q] energy on a Cu surface has been measured. Theoretically we have derived an analytic formula which allows us to calculate the 2[ital l]-[ital nl][prime], 3[ital l]-[ital nl][prime], and 4[ital l]-[ital nl][prime] ([ital n][le]5), [ital L], [ital M], and [ital N] x-ray transition energies averaged over spin and angular-momentum quantum numbers ([ital L] and [ital S]) as a function of the electron occupation numbers ([ital k][sub [ital i]]) for the states [ital Q]=1[ital s][sub 1][sup [ital k]]2[ital s][sub 2][sup [ital k]]2[ital p][sub 3][sup [ital k]]3[ital s][sub 4][sup [ital k]]3[ital p][sub 5][sup [ital k]]3[ital d][sub 6][sup [ital k]]4[ital s] [sub 7][sup [ital k]]4[ital p][sub 8][sup [ital k]]4[ital d][sub 9][sup [ital k]]4[ital f][sub 10][sup [ital k]]5[ital s][sub 11][sup [ital k]]5[ital p][sub 12][sup [ital k]]. In accordance with our theoretical predictions the observed [ital L] x-ray structures shift toward higher energies and increase in intensity relative to the [ital M] x rays with increasing charge state. We have also observed an increase in high-energy satellite-line intensities with the increasing number of 2[ital p] vacancies. In calculating the radiative-transition probabilities we have found that the dominating electric-dipolemore » transitions for [ital L] and [ital M] x rays are of the kind 2[ital p]-3[ital d] and 3[ital d]-4[ital f], respectively. A comparison between measured peak positions and calculated transition energies reveals that direct feeding by approximately 13 electrons can explain the main features of the observed x-ray emission spectra.« less

Xe L and M x-ray emission following Xe44-48+ ion impact on Cu surfaces.

Excitation energies of the [Xe]${\mathit{ns}}_{1/2}$, [Xe]${\mathit{np}}_{j}$, and [Xe]${\mathit{nd}}_{j}$ ($n\ensuremath{\leqslant}$ $12$ and $[\mathrm{Xe}]=1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}3{d}^{10}4{s}^{2}4{p}^{6}4{d}^{10}5{s}^{2}5{p}^{6}$) in Ba ii are evaluated. First-, second-, third-, and all-order Coulomb energies and first- and second-order Coulomb-Breit energies are calculated. Electric-dipole ($6{s}_{1/2}$-${\mathit{np}}_{j}$, $n=6$--26), electric-quadrupole ($6{s}_{1/2}$-${\mathit{nd}}_{j}$, $n=5$--$26$), and electric-octupole ($6{s}_{1/2}$-${\mathit{nf}}_{j}$, $n=4$--$26$) matrix elements are calculated to obtain the ground-state $E1$, $E2$, and $E3$ static polarizabilities. Scalar polarizabilities of the ${\mathit{ns}}_{1/2}$, ${\mathit{np}}_{j}$, and ${\mathit{nd}}_{j}$ states and tensor polarizabilities of the ${\mathit{np}}_{3/2}$ and ${\mathit{nd}}_{j}$ excited states of Ba${}^{+}$ are evaluated. All aforementioned matrix elements are determined using the relativistic all-order method. The hyperfine structure in $^{137}\mathrm{Ba}$ ii is also investigated. The hyperfine $A$ and $B$ values are determined for the first low-lying levels up to $n=9$. The quadratic Stark effect on hyperfine structure levels of $^{137}\mathrm{Ba}$ ii ground state is investigated. The calculated shift for the ($F=2$, $M=0$) $\ensuremath{\leftrightarrow}$ ($F=1$, $M=0$) transition is $\ensuremath{-}$$0.2931$ Hz/(kV/cm)${}^{2}$, in agreement with a previous theoretical result, $\ensuremath{-}0.284(3)$). These calculations provide a theoretical benchmark for comparison with experiment and theory.

Relativistic many-body calculation of energies, lifetimes, hyperfine constants, multipole polarizabilities, and blackbody radiation shift in Ba 137 ii

Many body perturbation theory in conjunction with the screening method has been applied to calculate radiative transition energies of highly charged ions. In the formulas obtained the energy values are averaged over LSJ as a function of the number of electrons distributed in up to 27 subshells taking relativistic energy shifts into account. The introduction of approximate screening parameters for nonrelativistic and relativistic parts of the energy allows us to limit our calculation to first order interelectron interaction only. The derived formulas have been proven to be very useful calculating X-ray spectra of Xeq+ (q = 44−48) ions interacting with the Cu surface. Comparison is made with other methods such as Hartree-Fock-Pauli (HFP), and relativistic model potential. Computational problems introducing different screening constants and asymptotic limits as well as contributions of the neglected second order interaction are discussed.

Screening theory for transition energies of highly charged ions

Excitation energies of the $[\mathrm{Kr}]{\mathit{ns}}_{1/2}$, $[\mathrm{Kr}]{\mathit{np}}_{j}$, $[\mathrm{Kr}]{\mathit{nd}}_{j}$, and $[\mathrm{Kr}]{\mathit{nf}}_{j}$ ($n\ensuremath{\leqslant}9$ and $[\mathrm{Kr}]=(1{s}^{2}2{s}^{2}2{p}^{6}3{s}^{2}3{p}^{6}3{d}^{10}4{s}^{2}4{p}^{6}$) in Sr ii are evaluated. First-order, second-order, third-order, and all-order Coulomb energies and first-order and second-order Coulomb-Breit energies are calculated. Reduced matrix elements, oscillator strengths, transition rates, and lifetimes are determined for the levels up to $n=7$. Electric-dipole ($5{s}_{1/2}\ensuremath{-}{\mathit{np}}_{j}$, $n=5--26$), electric-quadrupole ($5{s}_{1/2}\ensuremath{-}{\mathit{nd}}_{j}$, $n=4--26$), and electric-octupole ($5{s}_{1/2}\ensuremath{-}{\mathit{nf}}_{j}$, $n=4--26$) matrix elements are calculated to obtain the ground-state $E1$, $E2$, and $E3$ static polarizabilities. Scalar and tensor polarizabilities for the $5{p}_{j}\ensuremath{-}9{p}_{j}$ and $4{d}_{j}\ensuremath{-}8{d}_{j}$ excited states in Sr ii are also calculated. All the above-mentioned matrix elements are determined using the all-order method. We also investigate the hyperfine structure in $^{87}\mathrm{Sr}$${}^{+}$. The hyperfine $A$ values and $B$ values are determined for the first low-lying levels up to $n=7$. The quadratic Stark effect on hyperfine-structure levels of the $^{87}\mathrm{Sr}$${}^{+}$ ground state is investigated. The calculated shift for the $(F=5,M=0)\ensuremath{\leftrightarrow}(F=4,M=0)$ transition is found to be 0.120(1) Hz/(kV/cm)${}^{2}$. These calculations provide a theoretical benchmark for comparison with the experiment and theory. A careful study of uncertainty of our calculations is carried out for the transition-matrix elements, line strengths, transition rates, lifetimes, polarizabilities, and the Stark shift coefficient.

U I Safronova

Papers

Energy Levels of He- and Li-Like Ions (States 1snl, 1 s2nl with n = 2-5)

Xe L and M x-ray emission following Xe44-48+ ion impact on Cu surfaces.

Relativistic many-body calculation of energies, lifetimes, hyperfine constants, multipole polarizabilities, and blackbody radiation shift in Ba 137 ii

Screening theory for transition energies of highly charged ions

All-order perturbation calculation of energies, hyperfine constants, multipole polarizabilities, and blackbody radiation shift in Sr 87 +