Messung der Lebensdauer von Elektronen im 3P- und 4D-Zustand des Natrium

Karstensen, F.; Schramm, Jürgen

doi:10.1007/bf01330948

Cited by 19 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the above, y = (ln2) U2 u Q /[7TTAv D (p 1 -v 2 )] f where hv Q is the energy of the 3S-4D transition {v 0 = 1.036 xlO 15 Hz), r is the natural lifetime of the excited state (52 nsec), 8 and Av D is the Doppler width of the two-photon transition (~ 3.4 GHz). Over the tuning range used in our work 77 varied from 0.38 to 0.08.…”

Section: Stratedmentioning

confidence: 99%

Resonant Enhancement of Two-Photon Absorption in Sodium Vapor

Bjorkholm¹,

Liao²

1974

Phys. Rev. Lett.

205

View full text Add to dashboard Cite

tion of the form (21+ l)e' l/1° was necessary. No reason for this behavior was proffered and, subsequently, Ponomarev 9 has suggested that such a violent change in the initial I distribution, for nearby elements, seems unnatural. From the point of view of atomic dimensions, however, this is precisely the expectation, since the atomic diameters of Ti and Mn are 2.93 and 2.5 A, respectively. Thus, we would expect a truncation in I for the initial angular distribution in Mn which would be reflected later in the cascade by a diminished circular orbit population for Mn as compared to Ti.It may be possible to understand the reluctance of mesons to be captured into large angular momentum states in metals with small internuclear spacings on purely classical grounds. For a kaon to be captured into a state of I = 100H by an atom of radius 1 A requires the kaon to have a minimum kinetic energy of ~ 50 eV. Thus, if the kaon succeeds in escaping localization upon a single atom until it has a lower energy than this, capture into large-Z states would be quite unlikely. It should be pointed out that, even though there are many uncertainties in the calculations, several studies of the capture of slow negative mesons 6,10 have found that capture by a single atom occurs at energies somewhat in excess of this value.It would certainly be beneficial to extend mesonic atom x-ray intensity measurements to otherRecently there have appeared a number of papers demonstrating high-resolution two-photon spectroscopy in atomic vapors. 102 Especially interesting are the techniques which eliminate Doppler broadening by causing the atoms to absorb one photon from each of two beams of equal frequency propagating in opposite directions. 2 We have utilized a generalization of the opposing -targets and other incident projectiles (p, 2T, etc.). However, on the basis of the observations presented here, a study of the low-lying mesonic xray intensities in manganese or zinc in several of their crystalline forms should prove most interesting.beam technique to demonstrate resonant enhancement of the two-photon absorption cross section in sodium vapor. Our experiments were carried out using two single-mode, cw dye lasers operating at different frequencies. Large enhancements of more than 7 orders of magnitude and destructive-interference effects due to nearly resonant intermediate states are clearly demon -Resonant enhancement of over 7 orders of magnitude of the two-photon absorption cross section is observed in sodium vapor. Two cw dye-laser beams of different frequencies and propagating in opposite directions are utilized to generate high-resolution spectra which allow the enhancement as well as destructive-interference effects of nearly resonant intermediate states to be clearly demonstrated.128

show abstract

Section: Stratedmentioning

confidence: 99%

Resonant Enhancement of Two-Photon Absorption in Sodium Vapor

Bjorkholm¹,

Liao²

1974

Phys. Rev. Lett.

205

View full text Add to dashboard Cite

show abstract

“…A straightforward way for the determination of atomic lifetimes in Mg I is the observation of the time dependence of the reemitted resonance light after short pulse excitation. There are many methods to excite the atomic levels with a short pulse: One can use the electron impact with a pulsed electron beam [6], a pulsed discharge [7], or the wellknown beam foil-technique [8][9][10][11][12]. A common feature of all these methods is that no selection rules exclude the excitation of certain states.…”

Section: Introductionmentioning

confidence: 99%

“…In the case of Mg I we used the electron impact as the first step to excite the atoms to the metastable 3 s3p 3p-states. The second step was done by a pulsed tunable dye laser, which excited the atoms from the metastable 3s3p 3p-states to the 3snd 3D3.z,x-(n= [3][4][5][6][7] and the 3sns 3Sl-States (n=4 and 6). As the region of interaction of the atomic beam with the laser beam was well separated from the region where the metastable atoms were produced by electron impact, no cascade effects were present.…”

Section: Introductionmentioning

confidence: 99%

Lifetime measurements in the triplet system of Mg I

1980

View full text Add to dashboard Cite

show abstract

“…A35, page 6 of 10 (Volz et al 1996); [3] precision spectroscopy on an optically prepared sample of ultracold, two-level atoms (Oates et al 1996); [4] molecular spectroscopy of the Na 2 purely long-range O − g state (Jones et al 1996);[5] numerical Coulomb approximation (Lindgård & Nielsen 1977); [6] measurements by molecular beam method (Tiemann et al 1996);[7] realistic calculations including the core polarization, spin-orbit interaction, and blackbody radiation (Theodosiou 1984);[8] observing the decay in flight of laser-excited atoms in a fast atomic beam (Gaupp et al 1982);[9] multiconfiguration Hartree-Fock calculations (Carlsson et al 1992);[10] detecting the time-resolved fluorescence from the directly populated levels by the delayed-coincidence technique (Marek 1977);[11] multiconfiguration Hartree-Fock calculations (Jönsson et al 1996);[12] measurements by stepwise excitation of a fast ion beam (Kandela 1984);[13] direct oscillography of the time dependence of light emitted from Na atoms, excited by short pulses of electrons (Karstensen & Schramm 1966);[14] time resolved observations of the fluorescence radiation after stepwise excitation by two pulsed dye lasers (Kaiser 1975).…”

Section: Resultsmentioning

confidence: 99%

Na I spectra in the 1.4–14 micron range: transitions and oscillator strengths involving f-, g-, and h-states

Civiš

Ferus

Kubelík

et al. 2012

A&A

View full text Add to dashboard Cite

Context. Compared with the visible and ultraviolet ranges, fewer atomic and ionic lines are available in the infrared spectral region. Atlases of stellar spectra often provide only a short list of identified lines, and modern laboratory-based spectral features for wavelengths longer than 1 micron are not available for most elements. For the efficient use of the growing capabilities of infrared (IR) astronomy, detailed spectroscopical information on atomic line features in the IR region is needed. Aims. Parts of the infrared stellar (e.g., solar) spectra in the 1200-1800 cm −1 (5.6-8 μm) range have never been observed from the ground because of heavy contamination of the spectrum by telluric absorption lines. Such an infrared spectrum represents a great challenge for laboratory observations of new, unknown infrared atomic transitions involving the atomic levels with high orbital momentum and their comparison with the available spectra. Methods. The vapors of excited Na I atoms are produced during the ablation of the salt (sodium iodide, Na I) targets by a highrepetition rate (1.0 kHz) pulsed nanosecond ArF laser ExciStar S-Industrial V2.0 1000, pulse length 12 ns, λ = 193 nm, output energy of 15 mJ, fluence about 2-20 J/cm 2 inside a vacuum chamber (average pressure 10 −2 Torr). The time-resolved emission spectrum of the neutral atomic potassium (Na I) was recorded in the 700-7000 cm −1 region using the Fourier transform infrared spectroscopy technique with a resolution of 0.02 cm −1 . The f -values calculated in the quantum-defect theory approximation are presented for the transitions involving the reported Na I levels.Results. This study reports precision laboratory measurements for 26 Na I lines in the range of 700-7000 cm −1 (14-1.4 μm), including 20 lines not measured previously in the laboratory. This results in newly observed 7h, 6h, and 6g levels, and improved energy determination for ten previously known levels. The doublet structure of the 4f level has been observed for the first time. For transitions between the observed levels, we report calculated f -values that agree reasonably well with experiment. Conclusions. The recorded Na I line features agree with the data from the available solar spectrum atlases. The energy values of Na I 4s, 4p, 5p, 6p, 4f, 5f, and 5g levels extracted from our spectra have lower uncertainties as compared to the values reported several decades ago, but the latter values slightly differ from ours.

show abstract

Messung der Lebensdauer von Elektronen im 3P- und 4D-Zustand des Natrium

Cited by 19 publications

References 0 publications

Resonant Enhancement of Two-Photon Absorption in Sodium Vapor

Resonant Enhancement of Two-Photon Absorption in Sodium Vapor

Lifetime measurements in the triplet system of Mg I

Na I spectra in the 1.4–14 micron range: transitions and oscillator strengths involving f-, g-, and h-states

Contact Info

Product

Resources

About