Multiphoton ionization: mass selective laser-spectroscopy of Na2 and K2 in molecular beams

Herrmann, André; Leutwyler, Samuel; Schumacher, Ernst; Wöste, L.

doi:10.1016/0009-2614(77)80478-8

Cited by 112 publications

(17 citation statements)

References 15 publications

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“…It follows (see Table 3) that the shift of the 3D level is larger than that of the 4S level. The three-photon ionization signals differ from the corresponding 3D fluorescence signals concerning width and shape [32][33][34][35]. They are broader, indicating some ionization probability in the neighbourhood of the sharp two-photon resonance.…”

Section: Discussionmentioning

confidence: 91%

Two-photon intracavity dye laser spectroscopy of the 4S and 3D term in6, 7Li

et al. 1978

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Doppler-free two-photon spectroscopy of several states of 6,7Li has been achieved by placing an atomic beam inside the dye laser cavity. The hyperfine structure splitting of the 4S state, the fine structure splitting of the 3D level as well as the isotope shifts of the 2S-4S and 2S-3D transition have been measured, by scanning the single-mode laser frequency and detecting the fluorescence light. In addition, signal detection by threephoton ionization via the resonant 3D state was accomplished.

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Section: Discussionmentioning

confidence: 91%

Two-photon intracavity dye laser spectroscopy of the 4S and 3D term in6, 7Li

et al. 1978

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“…[43]. We have observed ( [2] and section 4) that at least the dimers are very cold: vibrational temperatures of < 100"K, and rotational temperature <40" K are found, so that >90% of the dimers are in the v"=O state, and less than 1% have v"=2. For this reason and because the energy range near threshold is very small, a step function is a good approximation, well supported within the experimental precision and resolution of the monochromator.…”

Section: Electron Impact Ionization/photoionizationmentioning

confidence: 90%

On Metal‐Atom Clusters IV. Photoionization thresholds and multiphoton ionization spectra of alkali‐metal molecules

Herrmann

Leutwyler

Schumacher

et al. 1978

Helvetica Chimica Acta

166

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In memory of Professor Heinrich Labhari (18.XI. 77) SummaryThe investigation of electronic and structural parameters of metal molecules as a function of size may be decisive for understanding and control of heterogeneous catalysis with finely divided metals. Metal-atom clusters can be prepared by several methods, most of which yield a molecular mixture only. Expansion of an atomic vapour into vacuum through a supersonic nozzle creates a complex cluster-spectrum which has been investigated by photoionization using a mass-spectrometer as selective detector. Broad band single photoionization (PI.) yields the abundances and ionization thresholds for Na,(xd 16), K,(xd 12) and Na,K, (x + y d 6). Rough indications about other deactivation channels of excited alkali-molecules are obtained from an analysis of the photoionization efficiency (PIE.) curves. Two-photon PIE. curves with narrow-band (laser) light sources give an accurate photoionization threshold value and detailed information on ionization processes. Two-photon ionization spectra via a real intermediate state reached by laser excitation are equivalent to normal absorption spectra, if the excitation step is controlled by the true transition probabilities. By investigation of the power dependence of the ion current of Na; as a function of the wavelength of the tunable cw dye laser (excitation) and of the ionizing Ar+-or Kr+-laser, conditions under which true spectra are obtained have been clarified, in good agreement with a photon-kinetic model of the processes involved. Vibronic and rovibronic spectra of several transitions in Na2 and K, have been measured. Similarly a spectrum of Na3 has been determined mass-selectively. The scope of the new method for an absorption spectroscopy in molecular beams is discussed.

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“…The dotted line is the envelope of the Na2 spectrum (600-680 nm) (Ref. 16). Note that the Na2 spectrum, dotted line, is an absorption spectrum (not a photodepletion spectrum; isolated Na2 would not be photodepleted) from Ref.…”

mentioning

confidence: 99%

“…Note that the Na2 spectrum, dotted line, is an absorption spectrum (not a photodepletion spectrum; isolated Na2 would not be photodepleted) from Ref. 16. The Na2 spectrum is not drawn to scale.…”

mentioning

confidence: 99%