Search results for "Names"
showing 10 items of 6843 documents
Rydberg and autoionizing states of tellurium studied by laser resonance ionization spectroscopy
2019
Multistep laser-resonance-ionization spectroscopy of tellurium (Te) has been performed at TRIUMF's off-line laser ion source test stand. Six clean and regular even-parity Rydberg series $5{p}^{3}$ $({^{4}S}_{3/2}^{\ensuremath{\circ}})$ $np\phantom{\rule{4pt}{0ex}}^{3}P_{0,1,2}$, $np\phantom{\rule{4pt}{0ex}}^{5}P_{1,2}$, and $nf\phantom{\rule{4pt}{0ex}}^{3}F_{2}/^{5}F_{1,2}$ were observed. The ionization potential of Te was extracted from the measured series as $72669.114{(56)}_{\mathrm{stat}}{(45)}_{\mathrm{sys}}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$. Excited from two different intermediate levels, seven odd-parity autoionization Rydberg series converging to the $5{s}^{2}…
Determination of the first ionization potential of technetium
2010
Using resonance ionization spectroscopy the first-ionization potential of actinium has been determined by analyzing different Rydberg series in two-color resonant laser excitation. Three individual Rydberg series were investigated, converging toward the ionic ground state and toward the first- and second-excited state of the actinium ion, respectively. A combined analysis of the convergence limits leads to a consistent value for the first-ionization potential of Ac of $43\phantom{\rule{0.16em}{0ex}}394.45\phantom{\rule{0.16em}{0ex}}(19)\phantom{\rule{0.28em}{0ex}}{\text{cm}}^{\ensuremath{-}1}$, equivalent to $5.380\phantom{\rule{0.16em}{0ex}}226\phantom{\rule{0.16em}{0ex}}(24)$ eV.
Total angular momenta of even-parity autoionizing levels and odd-parity high-lying levels of atomic uranium
2002
Using three-step resonance ionization spectroscopy, over 200 even-parity autoionizing (AI) levels of atomic uranium, including Rydberg series converging to the second lowest ionic level (6L 11/2o), were observed in the 49 930–51 200 cm−1 energy range. Total angular momenta (J values) of these levels were determined by a polarization combination method as well as a method based on the J-momentum selection rule. Using the AI levels of which J values were determined unambiguously, unique J values were also assigned for about 70 high-lying odd-parity levels. The observed J-dependence on autoionization linewidth is interpreted as being due to a centrifugal potential barrier.
Dependence of the shapes of nonzero-field level-crossing signals in rubidium atoms on the laser frequency and power density
2013
We studied magneto-optical resonances caused by excited-state level crossings in a nonzero magnetic field. Experimental measurements were performed on the transitions of the ${D}_{2}$ line of rubidium. These measured signals were described by a theoretical model that takes into account all neighboring hyperfine transitions, the mixing of magnetic sublevels in an external magnetic field, the coherence properties of the exciting laser radiation, and the Doppler effect. Good agreement between the experimental measurements and the theoretical model could be achieved over a wide range of laser power densities. We further showed that the contrasts of the level-crossing peaks can be sensitive to c…
Wavelength dependence of multiphoton ionization of xenon
2004
We have studied the multiphoton ionization of xenon atoms by $160\phantom{\rule{0.3em}{0ex}}\mathrm{fs}$ pulses at intensities of $5\ifmmode\times\else\texttimes\fi{}{10}^{12}$ and $1.3\ifmmode\times\else\texttimes\fi{}{10}^{13}\phantom{\rule{0.3em}{0ex}}\mathrm{W}∕{\mathrm{cm}}^{2}$ 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 $700\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$. Resonant and nonresonant processes as well as channel switching effects have been observed in this intensity and wavel…
Ionization of Rb and Na Rydberg atoms by blackbody radiation
2007
This work presents the results of the numerical calculations of (blackbody radiation) BBR-induced photoionization rates of Rb and Na Rydberg nS, nP and nD atoms with n = 8-65 at the ambient temperatures of 77, 300 and 600 K.
Rotational States of the Helium Trimer in the Symmetry-Adapted Hyperradial-Adiabatic Approach
2003
We have searched for bound rotationally excited states of the helium trimer using the symmetry-adapted hyperradial adiabatic approach. Since the calculated J p = 2+ and J p = 1− potential curves are both completely repulsive, we infer that there are no bound rotational states of 4He3. A recent adiabatic calculation [1] based on the direct solution of the Coriolis-coupled Schrodinger equation agrees with this conclusion.
Stochastic resonance in magnetic systems described by Preisach hysteresis model
2005
We present a numerical study of stochastic resonance in magnetic systems described by Preisach hysteresis model. It is shown that stochastic resonance occurs in these systems. Specifically, the signal-to-noise ratio sSNRd and the signal amplification sSAd present a maximum as a function of noise intensity. We also found that the hysteresis loops, dynamically described by the system, are strongly modified near the maxima of SNR and of SA.
A duality-invariant Einstein-Planck relation and its consequences on micro-black holes.
2013
We discuss the consequences of a duality-invariant Einstein–Planck (DIEP) relation on the equation of state of micro black holes. The results are analogous to those obtained from the "world-crystal" model, but with some significative differences, as for instance a limiting vanishing value for temperature for very small black holes. The model leads to a total evaporation of micro black holes but with the final stage being very slow.
Ionization of Rydberg atoms by blackbody radiation
2008
We have studied an ionization of alkali-metal Rydberg atoms by blackbody radiation (BBR). The results of the theoretical calculations of ionization rates of Li, Na, K, Rb and Cs Rydberg atoms are presented. Calculations have been performed for nS, nP and nD states which are commonly used in a variety of experiments, at principal quantum numbers n=8-65 and at the three ambient temperatures of 77, 300 and 600 K. A peculiarity of our calculations is that we take into account the contributions of BBR-induced redistribution of population between Rydberg states prior to photoionization and field ionization by extraction electric field pulses. The obtained results show that these phenomena affect …