Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

RESONANT LIGHT ABSORPTION BY AN EXCITIVE PENNING IONIZATION COLLISION

James H. Goble, William E. Hollingsworth, John S. Winn

Published Aug 1, 1981• 0 citations
OpenAlex

Abstract

We have observed the opening of a new channel of excitive Penning ionization by the collision complex absorption of laser light in the system Ar*(3p) + Ca.Two relatively broad bands at 5958 and 5990 A were found, corresponding to the production of ca+(5p 2 P 3 ; 2 ) and ca+(_5p 2 P 11 ~), respectively.Preliminary-estim~tes indicate that the laser-ass~sted Penning ionization cross-section exceeds that of the field-free ionization to ca+(4p 2p3/2).

Related papers

Resonant Light Absorption in a Penning-Ionization Collision

James H. Goble, William E. Hollingsworth, John S. Winn

The opening of a new channel of excitative Penning ionization by a collision-complex absorption of laser light has been observed in the system Ar*($^{3}P$) + Ca. Two relatively broad resonances at 5958 and 5990 \AA{} were found, corresponding to the production of ${\mathrm{Ca}}^{+}$($5p^{2}P_{\frac{3}{2}}$) and ${\mathrm{Ca}}^{+}$($5p^{2}P_{\frac{1}{2}}$), respectively. The data indicate that the laser-assisted Penning-ionization cross section to these states exceeds that of the field-free ionization to ${\mathrm{Ca}}^{+}$($4p^{2}P_{\frac{3}{2}}$).

Physical Review Letters•Dec 28, 1981•7 citations

Penning and associative ionization in crossed-beam Na/Na collisions assisted by strong resonant laser fields

J. Weiner, Penelope Polak-Dingels

We observe the production of Na2+ and Na+ arising from single collisions between crossed beams of sodium atoms when a laser field is tuned near the Na(3p 2P3/2) and Na(3p 2P1/2) transitions. Measurements of ion intensity vs laser intensity show that at moderately high power true laser-induced processes dominate over purely collisional effects. Relative intensity of mass-selected ions produced at either member of the Na resonance doublet shows conclusively that Na+ does not arise simply from photodissociation of Na2+ but must result from a direct, laser-induced collisional ionization.

The Journal of Chemical Physics•Jan 1, 1981•40 citations

Efficient collisional dissociation of Na{sub 2}{sup +} by laser-excited Na (3p)

Charles Tapalian, W. W. Smith

In studying ionization reactions in a single dense effusive beam of laser-excited Na(3p) atoms, we observe production of both Na{sub 2}{sup +} and Na{sup +} ions. The Na{sup +} results from the familiar associative ionization reaction of two Na(3p) atoms and the Na{sup +} ions under our conditions result mostly from the collisional dissociation of the Na{sub 2}{sup +} by reaction with a third excited Na(3p) atom, rather than from photo- dissociation or photoionization. A CW, single-frequency dye laser tuned to 589 nm resonantly excites the Na(3s) atoms to the 3p state. The atomic beam Na(3s) density is determined from low-intensity 589 absorption measurements. Na{sup +} ion yield depends on the cube of the Na beam density, suggesting successive collisions of three Na(3p) atoms: we believe the Na{sub 2}{sup +} ions polarize the third Na(3p) atom, resulting in a R{sup -4} orbiting collision interaction. A large collisional dissociation cross-section of approximately (4{plus_minus}2)x10{sup -13} cm{sup 2} results, for oven temperatures in the 500-600K range.

Bulletin of the American Physical Society•May 1, 1993•0 citations

Three-photon resonances due to autoionizing states in calcium

Anna M. Zawadzka, Roman S. Dygdała, Andrzej Raczyński +2 more

In the present study we have investigated three-photon ionization in Ca in which autoionizing states are engaged. The two-photon resonant process (from the Ca ground state 4s 2 1 S 0 ) occurred through or at least in the vicinity of one of the following states: 4s4d 1 D 2 , 4p 2 3 P 2 , 4s6s 1 S 0 , 4p 2 1 D 2 and 4p 2 1 S 0 , with the third photon either reaching the continuum directly or one of the autoionizing states. The three-photon resonant transitions to 3d m p, m f: 1 P 1 , 3 P 1 and 3 D 1 autoionizing states for m up to 21 have been observed. Some of the autoionizing resonances which we have found had not been observed before in a high-resolution one-photon absorption experiment (for J = 1) and in multiphoton experiments (for J = 3). We have compared the ionization signal as a function of the laser detuning and the laser intensity with theoretical curves obtained within a simple model (three-level atom + one-mode laser field). This gives information about the order of magnitude of the three-photon ionization probability through autoionizing states.

Journal of Physics B Atomic Molecular and Optical Physics•Apr 11, 2002•19 citations

Coherence Transfer in a Penning Ionizing Collision

L. D. Schearer, L. A. Riseberg

Modulation of the intensity of light emitted by ${\mathrm{Sr}}^{+}(^{2}P_{\frac{3}{2}})$ ions at the resonance frequency of metastable helium atoms has been observed, demonstrating that coherence has been transferred in the Penning collision. The coherent excitation of the Penning ions suggests that the techniques of "coherence spectroscopy" such as level-crossing and Hanle experiments can be extended to excited states of Penning ions which are currently inaccessible by means of optical excitation.

Physical Review Letters•Mar 15, 1971•24 citations

Ionizing Collisions Between Two Laser-Excited Atoms: Separation of Penning and Photoionization by High-Resolution Electron Spectrometry

H Dengel, M.‐W. Ruf, Hartmut Hotop

Using transverse laser excitation of a single collimated atomic sodium beam in combination with an efficient electron spectrometer, we have studied collisional (= Penning) and photoionization processes involving the laser-excited Na(3 p 3/2 ) and Na(3 d 5/2 ) atoms. As a result of our high electron energy resolution (6 meV) we have for the first time been able to measure the polarization-dependent lineshapes of the Penning electron spectra for collisions between two laser-excited atoms and to reliably separate overlapping contributions due to Penning and photoionization.

Europhysics Letters (EPL)•Sep 10, 1993•6 citations
We have observed the opening of a new channel of excitive Penning ionization by the collision complex absorption of laser light in the system Ar*(3p) + Ca.Two relatively broad bands at 5958 and 5990 A were found, corresponding to the production of ca+(5p 2 P 3 ; 2 ) and ca+(_5p 2 P 11 ), respectively.Preliminary-estimtes indicate that the laser-ass~sted Penning ionization cross-section exceeds that of the field-free ionization to ca+(4p 2p3/2).
The opening of a new channel of excitative Penning ionization by a collision-complex absorption of laser light has been observed in the system Ar*(3P^{3}P3P) + Ca. Two relatively broad resonances at 5958 and 5990 \AA{} were found, corresponding to the production of Ca+{\mathrm{Ca}}^{+}Ca+(5p2P325p^{2}P_{\frac{3}{2}}5p2P23​​) and Ca+{\mathrm{Ca}}^{+}Ca+(5p2P125p^{2}P_{\frac{1}{2}}5p2P21​​), respectively. The data indicate that the laser-assisted Penning-ionization cross section to these states exceeds that of the field-free ionization to Ca+{\mathrm{Ca}}^{+}Ca+(4p2P324p^{2}P_{\frac{3}{2}}4p2P23​​).
We observe the production of Na2+ and Na+ arising from single collisions between crossed beams of sodium atoms when a laser field is tuned near the Na(3p 2P3/2) and Na(3p 2P1/2) transitions. Measurements of ion intensity vs laser intensity show that at moderately high power true laser-induced processes dominate over purely collisional effects. Relative intensity of mass-selected ions produced at either member of the Na resonance doublet shows conclusively that Na+ does not arise simply from photodissociation of Na2+ but must result from a direct, laser-induced collisional ionization.
In studying ionization reactions in a single dense effusive beam of laser-excited Na(3p) atoms, we observe production of both Na{sub 2}{sup +} and Na{sup +} ions. The Na{sup +} results from the familiar associative ionization reaction of two Na(3p) atoms and the Na{sup +} ions under our conditions result mostly from the collisional dissociation of the Na{sub 2}{sup +} by reaction with a third excited Na(3p) atom, rather than from photo- dissociation or photoionization. A CW, single-frequency dye laser tuned to 589 nm resonantly excites the Na(3s) atoms to the 3p state. The atomic beam Na(3s) density is determined from low-intensity 589 absorption measurements. Na{sup +} ion yield depends on the cube of the Na beam density, suggesting successive collisions of three Na(3p) atoms: we believe the Na{sub 2}{sup +} ions polarize the third Na(3p) atom, resulting in a R{sup -4} orbiting collision interaction. A large collisional dissociation cross-section of approximately (4{plus_minus}2)x10{sup -13} cm{sup 2} results, for oven temperatures in the 500-600K range.
In the present study we have investigated three-photon ionization in Ca in which autoionizing states are engaged. The two-photon resonant process (from the Ca ground state 4s 2 1 S 0 ) occurred through or at least in the vicinity of one of the following states: 4s4d 1 D 2 , 4p 2 3 P 2 , 4s6s 1 S 0 , 4p 2 1 D 2 and 4p 2 1 S 0 , with the third photon either reaching the continuum directly or one of the autoionizing states. The three-photon resonant transitions to 3d m p, m f: 1 P 1 , 3 P 1 and 3 D 1 autoionizing states for m up to 21 have been observed. Some of the autoionizing resonances which we have found had not been observed before in a high-resolution one-photon absorption experiment (for J = 1) and in multiphoton experiments (for J = 3). We have compared the ionization signal as a function of the laser detuning and the laser intensity with theoretical curves obtained within a simple model (three-level atom + one-mode laser field). This gives information about the order of magnitude of the three-photon ionization probability through autoionizing states.
Modulation of the intensity of light emitted by Sr+(2P32){\mathrm{Sr}}^{+}(^{2}P_{\frac{3}{2}})Sr+(2P23​​) ions at the resonance frequency of metastable helium atoms has been observed, demonstrating that coherence has been transferred in the Penning collision. The coherent excitation of the Penning ions suggests that the techniques of "coherence spectroscopy" such as level-crossing and Hanle experiments can be extended to excited states of Penning ions which are currently inaccessible by means of optical excitation.
Using transverse laser excitation of a single collimated atomic sodium beam in combination with an efficient electron spectrometer, we have studied collisional (= Penning) and photoionization processes involving the laser-excited Na(3 p 3/2 ) and Na(3 d 5/2 ) atoms. As a result of our high electron energy resolution (6 meV) we have for the first time been able to measure the polarization-dependent lineshapes of the Penning electron spectra for collisions between two laser-excited atoms and to reliably separate overlapping contributions due to Penning and photoionization.