Search results for "Physics::Atomic Physics"
showing 10 items of 1181 documents
Developments for resonance ionization laser spectroscopy of the heaviest elements at SHIP
2016
Abstract The experimental determination of atomic levels and the first ionization potential of the heaviest elements ( Z ⩾ 100 ) is key to challenge theoretical predictions and to reveal changes in the atomic shell structure. These elements are only artificially produced in complete-fusion evaporation reactions at on-line facilities such as the GSI in Darmstadt at a rate of, at most, a few atoms per second. Hence, highly sensitive spectroscopic methods are required. Laser spectroscopy is one of the most powerful and valuable tools to investigate atomic properties. In combination with a buffer-gas filled stopping cell, the Radiation Detected Resonance Ionization Spectroscopy (RADRIS) techniq…
Impact of buffer gas quenching on the $^1S_0$ $\to$ $^1P_1$ ground-state atomic transition in nobelium
2017
International audience; Using the sensitive Radiation Detected Resonance Ionization Spectroscopy (RADRIS) techniquean optical transition in neutral nobelium (No, Z = 102) was identified. A remnant signal when delaying the ionizing laser indicated the influence of a strong buffer gas induced de-excitation of the optically populated level. A subsequent investigation of the chemical homologue, ytterbium (Yb, Z = 70), enabled a detailed study of the atomic levels involved in this process, leading to the development of a rate equation model. This paves the way for characterizing resonance ionization spectroscopy (RIS) schemes used in the studyof nobelium and beyond, where atomic properties are c…
<title>Deconvolution of the mercury 253.7 nm spectral line shape for the use in absorption spectroscopy</title>
2008
In this work we present measurement and results of the deconvolution of the Hg 253.7 nm spectral line shapes, emitted from the mercury isotope high-frequency electrodeless discharge lamps, made at the Institute of Atomic Physics and Spectroscopy for the use in Zeeman Atomic Absorption Spectrometry. The emission line profiles of 254 nm Hg resonance line have been measured by means of a Zeeman scanning spectrometer at the mercury cold spot temperature value at 20 C. Then the deconvolution procedure or solving of this ill-posed inverse problem by means of the Tikhonov's regularization method [1] was performed to obtain the real spectral line shape.© (2008) COPYRIGHT SPIE--The International Soc…
SELECTIVE AMPLIFICATION OF NARROW RESONANCE FORMED IN TRANSMISSION SPECTRUM OF Rb NANO-CELL IN MAGNETIC FIELD
2012
Recently it was shown that "λ-Zeeman Technique" (λ-ZT) is a convenient tool to study individual transitions between the Zeeman sublevels of hyperfine levels in an external magnetic field. λ-ZT is based on resonant transmission spectrum of nanometric thin cell (NTC) of thickness L = λ, where λ is the resonant wavelength 794 nm for Rb D1 line. Narrow velocity selective optical pumping (VSOP) resonances in the transmission spectrum of the NTC are split into several components in a magnetic field. Examination of VSOP resonances allows one to identify and investigate an atomic transition in the range of magnetic fields 10 - 5000 G. Here we present a new method for selective addressing of VSOP r…
Lattice dynamics of superconducting zirconium and hafnium nitride halides
2003
We have performed a study of the Raman active modes of β-HfNCl, β-ZrNCl, and β-ZrNBr and Na-doped β-HfNCl in various scattering configurations. The experimental values are compared with a lattice dynamical calculation andassigned to definite atomic motions. The variation of the atomic force constants are analyzed as a function of the bond length, relating their relative strength with the atomic characteristics of the compound.
Transient collisionally excited X-ray laser in nickel-like zirconium pumped with the PHELIX laser facility
2004
A transient collisionally excited X-ray laser has been put into operation using the front end of the PHELIX laser system as a pump laser. Strong lasing at 22 nm has been observed in nickel-like zirconium.
Isotope Shifts of Radium Monofluoride Molecules
2021
Isotope shifts of $^{223-226,228}$Ra$^{19}$F were measured for different vibrational levels in the electronic transition $A^{2}{}{\Pi}_{1/2}\leftarrow X^{2}{}{\Sigma}^{+}$. The observed isotope shifts demonstrate the particularly high sensitivity of radium monofluoride to nuclear size effects, offering a stringent test of models describing the electronic density within the radium nucleus. Ab initio quantum chemical calculations are in excellent agreement with experimental observations. These results highlight some of the unique opportunities that short-lived molecules could offer in nuclear structure and in fundamental symmetry studies.
Charge radius of the short-lived $^{68}$Ni and correlation with the dipole polarizability
2020
We present the first laser spectroscopic measurement of the neutron-rich nucleus $^{68}$Ni at the \mbox{$N=40$} subshell closure and extract its nuclear charge radius. Since this is the only short-lived isotope for which the dipole polarizability $\alpha_{\rm D}$ has been measured, the combination of these observables provides a benchmark for nuclear structure theory. We compare them to novel coupled-cluster calculations based on different chiral two- and three-nucleon interactions, for which a strong correlation between the charge radius and dipole polarizability is observed, similar to the stable nucleus $^{48}$Ca. Three-particle--three-hole correlations in coupled-cluster theory substant…
A Hirshfeld partitioning of polarizabilities of water clusters
2006
International audience; A new Hirshfeld partitioning of cluster polarizability into intrinsic polarizabilities and charge delocalization contributions is presented. For water clusters, density-functional theory calculations demonstrate that the total polarizability of a water molecule in a cluster depends upon the number and type of hydrogen bonds the molecule makes with its neighbors. The intrinsic contribution to the molecular polarizability is transferable between water molecules displaying the same H-bond scheme in clusters of different sizes, and geometries, while the charge delocalization contribution also depends on the cluster size. These results could be used to improve the existin…
Wavelength dependence of multiphoton ionization of xenon
2004
International audience; We have studied the multiphoton ionization of xenon atoms by 160 fs pulses at intensities of 531012 and 1.331013 W/cm2 and present photoelectron kinetic energy and angular distribution spectra measured with a photoelectron imaging spectrometer. A noncollinear optical parametric amplifier allows us to tune the wavelength of the laser pulse over a range between 500 and 700 nm. Resonant and nonresonant processes as well as channel switching effects have been observed in this intensity and wavelength regime. Mainly resonant s5+1d-photon ionization via ns, nd, and nd8 Rydberg states was studied in the region of 505–602 nm. Resonance structures were found related to the tw…