Spectroscopic Identification of Excited Atomic and Molecular States in Electron-Bombarded Liquid Helium

Dennis, Wiley Sam; Durbin, Edgar; Fitzsimmons, W. A.; Heybey, O.; Walters, G. K.

doi:10.1103/physrevlett.23.1083

Cited by 122 publications

(62 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of hot bands indicates vibrational temperatures of several 1000 K and thus relatively inefficient relaxation of the vibrational energy. Hot bands in the luminescence spectrum of electron bombarded liquid helium were reported by Dennis and co-workers [7]. They were also seen in the luminescence spectrum of photo excited He clusters and droplets [14].…”

Section: Methodsmentioning

confidence: 62%

“…Such a low current gives hope that the plasma formation process is much less pronounced in liquid He than in liquid Ar and there is the possibility to produce localized excitations in the liquid phase which are known to produce intense luminescence in the visible and near infrared spectral range. This luminescence has been observed from superfluid 4 He bombarded with energetic electrons [7][8][9], from liquid helium excited by a corona discharge [10][11][12][13], from 3 He and 4 He clusters and droplets excited by monochromatic synchrotron…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spectroscopic investigation of liquid helium excited by a corona discharge: evidence for bubbles and “red satellites”

Bonifaci

Aitken

et al. 2009

Eur. Phys. J. Appl. Phys.

View full text Add to dashboard Cite

Abstract. The establishment of corona discharges close to a point electrode under both negative and positive high voltage in normal liquid helium (LHe) at 4.2 K is reported. The experiments were carried out at constant temperature and pressures ranging from 0.1-10 MPa. Visible luminescence emitted from the zone close to the tip revealed lines due to excited He atoms and molecules. The molecular luminescence showed hot band emissions with vibrational levels populated up to v = 2. Rotational temperatures of 800 K were estimated showing that the excitations do not thermalise. With increasing pressure the lines shifted to shorter wavelengths and became broader. The magnitude of the increase in width deviated from what is expected from the gas phase and from classical line broadening theory and rather showed similarities to the behavior of bubbles in LHe. The detailed analysis of the rotational line intensity distribution revealed the presence of an additional radiator at the long wavelength side of molecular bands that we tentatively assign to "red satellite" emission. For corona discharges with positive tip polarities both atomic and molecular lines showed "red satellite" bands with much larger intensity than for negative polarity. The origin of the red satellite and the polarity dependence is unclear yet.

show abstract

Section: Methodsmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Spectroscopic investigation of liquid helium excited by a corona discharge: evidence for bubbles and “red satellites”

Bonifaci

Aitken

et al. 2009

Eur. Phys. J. Appl. Phys.

View full text Add to dashboard Cite

show abstract

“…The features are broadened and shifted depending on te hydrostatic pressure. Classical line broadening theory cannot explain the magnitudes of the line shifts and widths and we find that the most likely origin of the perturbation is the presence of bubbles around the emitting species similar to the observation by Dennis et al [1] who used electron bombardment for the excitation of superfluid helium. We further show that additional red-shifted spectral features exist that cannot be explained by rotational line intensity distributions of thermalized excimer molecules.…”

Section: Introductionmentioning

confidence: 63%

“…The different behavior of He is due to the excimer molecules being formed after the electronic excitation. Likewise, the rotational temperatures in the molecular bands observed in LHe or He droplets were by two orders of magnitude higher than the temperature of the liquid or the droplets [1].…”

Section: General Remarksmentioning

confidence: 99%

“…A particular feature of liquid helium is its intense luminescence in the visible and near infrared spectral range. This luminescence has been observed from superfluid 4 He bombarded with energetic electrons [1][2][3], from liquid helium excited by a corona discharge [4][5][6][7][8] as well as from 4 He droplets excited by monochromatic synchrotron radiation [9][10][11]. After electronic excitation, Rydberg-type He atoms or excimer molecules are formed in liquid helium and a repulsive force between the Rydberg electron orbital and the surrounding ground state helium atoms is established.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Luminescence from Liquid Helium Excited by Corona Discharges

Bonifaci

Aitken

et al. 2009

IEEE Trans. Dielect. Electr. Insul.

View full text Add to dashboard Cite

Liquid helium (LHe) at 4.2 K was electronically excited using a corona discharge for both negative and positive high voltages. The experiments were carried out for different pressures in the range from 0.1 to 10 MPa at constant temperature. The light emitted from the zone close to the tip was spectroscopically analyzed showing features from atoms and excimer helium. The shifts and widths of the observed lines and bands were found to depend on the applied hydrostatic pressure and on the tip polarity. Our analysis showed that classic pressure broadening theory cannot account for the observed widths and shifts rather than the presence of bubbles which surround single excited atoms and molecules. For positive tip polarities red shifted features distinct from pure He and He 2 * were observed and tentatively assigned to "red satellites".

show abstract

Chemistry and physics of dopants embedded in helium droplets

Albertini

Gruber

Zappa

et al. 2021

Mass Spectrometry Reviews

View full text Add to dashboard Cite

Helium droplets represent a cold inert matrix, free of walls with outstanding properties to grow complexes and clusters at conditions that are perfect to simulate cold and dense regions of the interstellar medium. At sub-Kelvin temperatures, barrierless reactions triggered by radicals or ions have been observed and studied by optical spectroscopy and mass spectrometry. The present review summarizes developments of experimental techniques and methods and recent results they enabled.

show abstract

Spectroscopic Identification of Excited Atomic and Molecular States in Electron-Bombarded Liquid Helium

Cited by 122 publications

References 11 publications

Spectroscopic investigation of liquid helium excited by a corona discharge: evidence for bubbles and “red satellites”

Spectroscopic investigation of liquid helium excited by a corona discharge: evidence for bubbles and “red satellites”

Luminescence from Liquid Helium Excited by Corona Discharges

Chemistry and physics of dopants embedded in helium droplets

Contact Info

Product

Resources

About