The state dependence of the interaction of metastable rare gas atoms Rg*(ms3 P 2,3 P 0) (Rg=Ne, Ar, Kr, Xe) with ground state sodium atoms

Abstract

The state dependence of the interaction of metastable rare gas atoms Rg* (ms 3P2, 3P0) (Rg = Ne, Ar, Kr, Xe) with ground state sodium atoms Schohl, S.; Müller, M.W.; Meijer, H.A.J.; Ruf, M.-W.; Hotop, H.; Morgner, H. Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Schohl, S., Müller, M. W., Meijer, H. A. J., Ruf, M-W., Hotop, H., & Morgner, H. (1990). The state dependence of the interaction of metastable rare gas atoms Rg* (ms 3P2, 3P0) (Rg = Ne, Ar, Kr, Xe) with ground state sodium atoms. Default journal. CopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Using crossed beams of metastable rare gas atoms Rg*(ms 3P2, 3Po) (Rg=Ne, Ar, Kr, Xe) and ground state sodium atoms Na(3s 2S1/2), we have measured the energy spectra of electrons released in the respective Penning ionization processes at thermal collision energies. For Rg*(3P2)+Na(3s), the spectra are quite similar for the different rare gases, both in width and shape; they reflect attractive interactions in the entrance channel with well depths D* [meV] decreasing slowly from R g = N e to Xe as follows: 676(18); 602(23); 565(26); 555(30). For Rg*(3~)+Na(3s), the spectra vary strongly with the rare gas, indicating a change in the character of the interaction from van der Waals type attraction (Ne) to chemical binding for Kr and Xe with well depths D* [meV] of: 51(I9); 107(25); 432(30); 530(50). These findings are explained through model calculations of the respective potential curves, in which the exchange and the spin orbit interaction in the excited rare gas and the molecular interaction between the two valence s-electrons in terms of suitably chosen singlet and triplet potentials are taken into account. These calculations also explain qualitatively the experimental finding that the ratios q2/qo of the ionization cross sections for Rg* (3P2)+Na and Rg* (3Po)+ Na vary strongly with the rare gas fromNe to Xe as follows: 15.8(3.2); 2.6(4); 1.4(2); 1.6(4).

Penning ionization and photoionization electron spectrometry of hydrogen fluoride

“…which is a direct, simple and useful prescription to estimate well depths for Penning ionizing quasi-molecules, as exploited, e.g., for He (2 3S, 2 1S) + alkali atoms [34] and for Rg* + Na (3s) [44] (Rg* = metastable 3P 2 and 3P 0 of Ne, Ar, Kr, Xe) For triatomic Penning ionization systems, as discussed here, the potential surfaces depend on two variables, i.e. on the distance R (taken to be the distance between the center of the metastable rare gas atom Rg* and the midpoint of the diatomic target molecule) and on the angle O between the vector R and the molecular axis r (we choose O = 0 ° to correspond to the coil±near conformation Rg* -H -F, while O = 180 ° describes coil±near Rg* approach towards the F-end).…”

Angle-dependent electron energy spectra resulting from autoionizing Ne⋆ (3s 3 P 2) +H(12 S) collisions

“…The metastable neon atoms are produced in a differentially pumped cold cathode dc discharge. The metastable beam contains neon atoms in the 3P 2-and 3Po-state, favouring the 3P2 species (j(3~)/j(3Po)~ 5/1 [23,27]). Since, in addition, the cross section a2 for Ne*(3P2)+ H collisions is considerably larger than the corresponding cross section ao for Ne*(3Po) + H, i.e.…”

“…In particular, rather detailed information exists for the basic processes He*(2 3S, 21S)+H/D [10,13,[18][19][20], which may be regarded as prototype systems for autoionizing collision complexes at thermal energies, while less effort was devoted to the investigation of heavier metastable noble gases [21][22][23][24][25].…”

Absolute detection of metastable rare gas atoms by a cw laser photoionization method

“…The metastable atom beam was collimated by a 2mm wide and 1 mm high slit at a distance of 348 mm from the source exit hole (solid angle 1.7.10-Ssr). Table 6 summarizes the relevant quantities needed in the procedure Present results of the total, photon-corrected detector currents for fresh graphite surface and comparable source gas densities b Flux into a solid angle of 1.7-10 -5 sr ° [201 a [13,19,20] o Evaluated for the region of laser photoionization (distance from source 348 ram); average velodties as given in (7) and the determined fluxes F 2 and densities n 2. Interestingly, almost equal densities are found for Ne*, At*, and Kr*.…”

“…Reactions of metastable rare gas atoms Rg* with photons, electrons, atoms, molecules, and surfaces are ac-* Dedicated to Prof. Dr. Wilhelm Hanle on the occasion of his 90th birthday "~" Present address: Fysisk Laboratorium, H.C. Orsted Institutet, DK-2100 Copenhagen, Denmark *'~ Permanent address: Joint Institute for Laboratory Astrophysics, University of Colorado, Boulder, 80309-0440, USA tively studied by molecular beam techniques [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16].…”