Physical Review Letters

Laser-Induced Charge Transfer to an Excited Ionic State

William R. Green, M. D. Wright, J. F. Young, Stephen E. Harris

Published Jul 9, 1979• 33 citations

Abstract

We report the observation of a laser-induced charge-transfer collision. In the presence of an intense laser beam, ground-state calcium ions collide with ground-state strontium atoms, selectively producing excited strontium ions and calcium neutrals. The laser-induced collision cross section has a linewidth of about 50 ${\mathrm{cm}}^{\ensuremath{-}1}$ and peaks \ensuremath{\sim} 70 ${\mathrm{cm}}^{\ensuremath{-}1}$ from that wavelength which satisfies the energy defect of the separated atoms.

DOI: 10.1103/physrevlett.43.120

Related papers

Laser-induced charge-transfer collisions of calcium ions with strontium atoms

M. D. Wright, D. M. O'Brien, J. F. Young +1 more

Physical Review AOct 1, 19816 citations

Observation of a laser-induced dipole–quadrupole collision

William R. Green, M. D. Wright, Jacques Lukasik +2 more

Experimental observation of a laser-induced dipole-quadrupole collision between Sr and Ca is reported. The laser-induced collision cross section peaks at an applied photon energy equal to the energy defect of the initial and final states of the infinitely separated atoms. A cross section of 3 x 10(-14) cm(2) was induced at a laser-power density of 7 x 10(9) W/cm(2); the linewidth was 20 cm(-1).

Optics LettersSep 1, 197932 citations

Laser assists excitation transfer in collisions

H. Richard Leuchtag

Physics TodayOct 1, 19761 citation

Laser-induced collisional energy transfer in Sr—Li system

Deying Chen, Zhen-Zhong Lu, Rongwei Fan +3 more

Chinese Physics BAug 1, 20121 citation

Laser-induced collisional-energy transfer in thermal collisions of lithium and strontium

Friedhelm Dorsch, S. Geltman, P. E. Toschek

Physical Review AApr 1, 198835 citations

Observation of laser-induced inelastic collisions

R. W. Falcone, William R. Green, J. C. White +2 more

Physical Review AMar 1, 1977136 citations

Physical Review Letters

Laser-Induced Charge Transfer to an Excited Ionic State

William R. Green, M. D. Wright, J. F. Young, Stephen E. Harris

Published Jul 9, 1979• 33 citations

Publisher

Abstract

{\mathrm{cm}}^{\ensuremath{-}1}

and peaks \ensuremath{\sim} 70

{\mathrm{cm}}^{\ensuremath{-}1}

from that wavelength which satisfies the energy defect of the separated atoms.

DOI: 10.1103/physrevlett.43.120

Related papers

Laser-induced charge-transfer collisions of calcium ions with strontium atoms

M. D. Wright, D. M. O'Brien, J. F. Young +1 more

Experimental studies of two laser-induced charge-transfer reactions in Ca and Sr are presented. In both reactions, a Ca ion collides with an Sr neutral in the presence of a laser field to produce a Ca neutral and an excited Sr ion. The two reactions differ in the final level of the ${\mathrm{Sr}}^{+}$ species. The collision cross sections associated with these reactions are studied as functions of applied laser frequency and power density. The largest cross section induced is equal to ${10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{2}$ , obtained at a power density of 2\ifmmode\times\else\texttimes\fi{} ${10}^{9}$ W/ ${\mathrm{cm}}^{2}$ . Differences in experimental results associated with the two reactions are explained qualitatively by an examination of the potential curves of the Ca ${\mathrm{Sr}}^{+}$ quasimolecule.Experimental studies of two laser-induced charge-transfer reactions in Ca and Sr are presented. In both reactions, a Ca ion collides with an Sr neutral in the presence of a laser field to produce a Ca neutral and an excited Sr ion. The two reactions differ in the final level of the ${\mathrm{Sr}}^{+}$ species. The collision cross sections associated with these reactions are studied as functions of applied laser frequency and power density. The largest cross section induced is equal to ${10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{2}$, obtained at a power density of 2\ifmmode\times\else\texttimes\fi{}${10}^{9}$ W/${\mathrm{cm}}^{2}$. Differences in experimental results associated with the two reactions are explained qualitatively by an examination of the potential curves of the Ca${\mathrm{Sr}}^{+}$ quasimolecule.

Physical Review AOct 1, 19816 citations

Observation of a laser-induced dipole–quadrupole collision

William R. Green, M. D. Wright, Jacques Lukasik +2 more

Optics LettersSep 1, 197932 citations

Laser assists excitation transfer in collisions

H. Richard Leuchtag

In an experiment that introduces a completely new approach to inelastic collisions, the transfer of excitation from one atom to another has been enormously enhanced by resonant optical irradiation. Incident laser light was tuned to a wavelength corresponding to the energy difference between the final and initial states of the colliding atoms. The experiments, in which the 5p strontium atoms transferred their excitation energy to 6s calcium atoms, was performed at Stanford University by Stephen Harris, Roger Falcone, William Green, Derek Lidow, Jonathan White and James Young.In an experiment that introduces a completely new approach to inelastic collisions, the transfer of excitation from one atom to another has been enormously enhanced by resonant optical irradiation. Incident laser light was tuned to a wavelength corresponding to the energy difference between the final and initial states of the colliding atoms. The experiments, in which the 5p strontium atoms transferred their excitation energy to 6s calcium atoms, was performed at Stanford University by Stephen Harris, Roger Falcone, William Green, Derek Lidow, Jonathan White and James Young.

Physics TodayOct 1, 19761 citation

Laser-induced collisional energy transfer in Sr—Li system

Deying Chen, Zhen-Zhong Lu, Rongwei Fan +3 more

A four-state model considering the relative velocity distribution function for calculating the cross section of laser-induced collisional energy transfer in a Sr—Li system is presented and profiles of laser-induced collision cross section are obtained. The resulting spectra obtained from different intermediate states are strongly asymmetrical in an opposite asymmetry. Both of the two intermediate states have contributions to the final state, and none of the intermediate states should be neglected. The peak of the laser-induced collisional energy transfer (LICET) profile shifts toward the red and the FWHM becomes narrower obviously with laser field intensity increasing. A cross section of 1.2 × 10−12 cm2 at a laser field intensity of 2.17 × 107 V/m is obtained, which indicates that this collision process can be an effective way to transfer energy selectively from a storage state to a target state. The existence of saturation for cross section with the increase of the laser intensity shows that the high-intensity redistribution of transition probabilities is an important feature of this process, which is not accounted for in a two-state treatment.A four-state model considering the relative velocity distribution function for calculating the cross section of laser-induced collisional energy transfer in a Sr—Li system is presented and profiles of laser-induced collision cross section are obtained. The resulting spectra obtained from different intermediate states are strongly asymmetrical in an opposite asymmetry. Both of the two intermediate states have contributions to the final state, and none of the intermediate states should be neglected. The peak of the laser-induced collisional energy transfer (LICET) profile shifts toward the red and the FWHM becomes narrower obviously with laser field intensity increasing. A cross section of 1.2 × 10−12 cm2 at a laser field intensity of 2.17 × 107 V/m is obtained, which indicates that this collision process can be an effective way to transfer energy selectively from a storage state to a target state. The existence of saturation for cross section with the increase of the laser intensity shows that the high-intensity redistribution of transition probabilities is an important feature of this process, which is not accounted for in a two-state treatment.

Chinese Physics BAug 1, 20121 citation

Laser-induced collisional-energy transfer in thermal collisions of lithium and strontium

Friedhelm Dorsch, S. Geltman, P. E. Toschek

Fluorescence of Li excited by laser light and simultaneous thermal ${\mathrm{Sr}}^{\mathrm{*}}$ collisions in the reaction Sr(5p)+Li(2s)+\ensuremath{\Elzxh}\ensuremath{\omega} (\ensuremath{\lambda}=669.8 nm)\ensuremath{\rightarrow}Sr(5 ${s}^{2}$ )+Li(4d) shows an asymmetric excitation spectrum of the energy transfer versus \ensuremath{\lambda}. The peak variation with light intensity demonstrates the strong-field regime and verifies current models. A change in the slope of the quasistatic wing agrees with the result of a recent three-level model.Fluorescence of Li excited by laser light and simultaneous thermal ${\mathrm{Sr}}^{\mathrm{*}}$ collisions in the reaction Sr(5p)+Li(2s)+\ensuremath{\Elzxh}\ensuremath{\omega} (\ensuremath{\lambda}=669.8 nm)\ensuremath{\rightarrow}Sr(5${s}^{2}$)+Li(4d) shows an asymmetric excitation spectrum of the energy transfer versus \ensuremath{\lambda}. The peak variation with light intensity demonstrates the strong-field regime and verifies current models. A change in the slope of the quasistatic wing agrees with the result of a recent three-level model.

Physical Review AApr 1, 198835 citations

Observation of laser-induced inelastic collisions

R. W. Falcone, William R. Green, J. C. White +2 more

We describe two new experiments which demonstrate laser-induced inelastic collisions. Energy was stored in the Sr $5p^{1}P^{o}$ state and selectively transferred both to the Ca $4{p}^{2}^{1}S$ and $5d^{1}D$ states. The collision cross sections maximized at the interatomic wavelengths of 4977 and 4711 \AA{}, respectively, and had a half-power width of about 14 ${\mathrm{cm}}^{\ensuremath{-}1}$.We describe two new experiments which demonstrate laser-induced inelastic collisions. Energy was stored in the Sr $5p^{1}P^{o}$ state and selectively transferred both to the Ca $4{p}^{2}^{1}S$ and $5d^{1}D$ states. The collision cross sections maximized at the interatomic wavelengths of 4977 and 4711 \AA{}, respectively, and had a half-power width of about 14 ${\mathrm{cm}}^{\ensuremath{-}1}$.

Physical Review AMar 1, 1977136 citations

{\mathrm{cm}}^{\ensuremath{-}1}

and peaks \ensuremath{\sim} 70

{\mathrm{cm}}^{\ensuremath{-}1}

from that wavelength which satisfies the energy defect of the separated atoms.

{\mathrm{Sr}}^{+}

species. The collision cross sections associated with these reactions are studied as functions of applied laser frequency and power density. The largest cross section induced is equal to ${10}^{\ensuremath{-}16}$

{\mathrm{cm}}^{2}

, obtained at a power density of 2\ifmmode\times\else\texttimes\fi{}

{10}^{9}

{\mathrm{cm}}^{2}

. Differences in experimental results associated with the two reactions are explained qualitatively by an examination of the potential curves of the Ca

{\mathrm{Sr}}^{+}

quasimolecule.

Fluorescence of Li excited by laser light and simultaneous thermal

{\mathrm{Sr}}^{\mathrm{*}}

collisions in the reaction Sr(5p)+Li(2s)+\ensuremath{\Elzxh}\ensuremath{\omega} (\ensuremath{\lambda}=669.8 nm)\ensuremath{\rightarrow}Sr(5

{s}^{2}

)+Li(4d) shows an asymmetric excitation spectrum of the energy transfer versus \ensuremath{\lambda}. The peak variation with light intensity demonstrates the strong-field regime and verifies current models. A change in the slope of the quasistatic wing agrees with the result of a recent three-level model.

We describe two new experiments which demonstrate laser-induced inelastic collisions. Energy was stored in the Sr

5p^{1}P^{o}

state and selectively transferred both to the Ca $4{p}^{2}^{1}S$ and

5d^{1}D

states. The collision cross sections maximized at the interatomic wavelengths of 4977 and 4711 \AA{}, respectively, and had a half-power width of about 14 ${\mathrm{cm}}^{\ensuremath{-}1}$.