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The interaction of metastable helium atoms with alkaline earth atoms: He(2 3S, 2 1S) + Mg, Ca, Sr and Ba


Ruf, Martin W.; Yencha, Andrew J.; Hotop, Hartmut; Movre, Mladen; Kerner, Christoff; Zillig, Sandra; Meyer, Wilfried
The interaction of metastable helium atoms with alkaline earth atoms: He(2 3S, 2 1S) + Mg, Ca, Sr and Ba // Zeitschrift für Physik D : atoms, molecules & clusters, 37 (1996), 3; 219-230 (međunarodna recenzija, članak, znanstveni)


Naslov
The interaction of metastable helium atoms with alkaline earth atoms: He(2 3S, 2 1S) + Mg, Ca, Sr and Ba

Autori
Ruf, Martin W. ; Yencha, Andrew J. ; Hotop, Hartmut ; Movre, Mladen ; Kerner, Christoff ; Zillig, Sandra ; Meyer, Wilfried

Izvornik
Zeitschrift für Physik D : atoms, molecules & clusters (0178-7683) 37 (1996), 3; 219-230

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Penning ionization; cross section; thermal energy collisions

Sažetak
We have carried out experimental and theoretical studies of Penning ionization processes occuring in thermal energy collisions of state-selected metastable He(2 3S) and He(2 1S) atoms with ground state alkaline earth atoms X (X= Mg, Ca, Sr, Ba). Penning ionization electron energy spectra for these eight systems, measured with a crossed-beam set-up perpendicular to the collision velocity at energy resolutions 40-70 meV, are reported; relative populations of the different ionic X(+) (ml) states are presented and well depths De for the He +X entrance channel potentials with uncertainties around 25 meV are derived from the electron spectra as follows: He(2 3S) + Mg/Ca/Sr/Ba : 130/250/240/260 meV; : He(2 1S) + Mg/Ca/Sr/Ba : 300/570/550/670 meV. The spectra show substantial differences for the free ionic states X(+)(2S), X(+)(2P) and X(+)(2D) and reveal that transitions to a repulsive potential - attributed to He + X(+)(2P) 2Sigma formation - are mainly involved for the X(+)(2P) channel. Ab initio calculations of potential curves, autoionization widths, electron energy spectra and ionization cross sections are reported for the systems He(2 3S) + Ca and He(2 1S) + Ca. The respective well depths De are calculated to be 243(15) meV and 544(15) meV; the ionization cross sections at the experimental mean energy of 72 meV amount to 101 x10(-16) cm(2) and 201x10(-16) cm(2), respectively. Very good overall agreement with the experimental electron spectra is observed.

Izvorni jezik
Engleski

Znanstvena područja
Fizika



POVEZANOST RADA


Projekt / tema
00350101

Ustanove
Institut za fiziku, Zagreb

Autor s matičnim brojem:
Mladen Movre, (32514)

Časopis indeksira:


  • Current Contents Connect (CCC)
  • Web of Science Core Collection (WoSCC)
    • SCI-EXP, SSCI i/ili A&HCI
  • Scopus