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Title: The Reaction of Dissociative Recombination in a Strong Light Field

Abstract

The DR theory of slow electrons with molecular ions in strong monochromatic light field is developed. The potential energy curves of the oxygen molecule O{sub 2}** dissociative states are calculated. Classification of all possible transitions and reaction mechanisms are presented.

Authors:
;  [1];  [2]; ;  [3]; ;  [4]
  1. Semenov Institute of Chemical Physics, RAS, Moscow (Russian Federation)
  2. (Russian Federation)
  3. Lomonosov Moscow State University, Moscow (Russian Federation)
  4. Moscow State Pedagogical University, Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
21251545
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1058; Journal Issue: 1; Conference: 19. international conference on spectral line shapes, Valladolid (Spain), 15-20 Jun 2008; Other Information: DOI: 10.1063/1.3026423; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ELECTRON-ION COLLISIONS; ELECTRONS; IONOSPHERE; MOLECULAR IONS; MONOCHROMATIC RADIATION; OXYGEN; POTENTIAL ENERGY; REACTION KINETICS; RECOMBINATION

Citation Formats

Golubkov, M. G., Golubkov, G. V., RSUTS, Moscow region, Adamson, S. O., Ryabinkin, I. G., Apukhtina, N. V., and Dementiev, A. I.. The Reaction of Dissociative Recombination in a Strong Light Field. United States: N. p., 2008. Web. doi:10.1063/1.3026423.
Golubkov, M. G., Golubkov, G. V., RSUTS, Moscow region, Adamson, S. O., Ryabinkin, I. G., Apukhtina, N. V., & Dementiev, A. I.. The Reaction of Dissociative Recombination in a Strong Light Field. United States. doi:10.1063/1.3026423.
Golubkov, M. G., Golubkov, G. V., RSUTS, Moscow region, Adamson, S. O., Ryabinkin, I. G., Apukhtina, N. V., and Dementiev, A. I.. Wed . "The Reaction of Dissociative Recombination in a Strong Light Field". United States. doi:10.1063/1.3026423.
@article{osti_21251545,
title = {The Reaction of Dissociative Recombination in a Strong Light Field},
author = {Golubkov, M. G. and Golubkov, G. V. and RSUTS, Moscow region and Adamson, S. O. and Ryabinkin, I. G. and Apukhtina, N. V. and Dementiev, A. I.},
abstractNote = {The DR theory of slow electrons with molecular ions in strong monochromatic light field is developed. The potential energy curves of the oxygen molecule O{sub 2}** dissociative states are calculated. Classification of all possible transitions and reaction mechanisms are presented.},
doi = {10.1063/1.3026423},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1058,
place = {United States},
year = {Wed Oct 22 00:00:00 EDT 2008},
month = {Wed Oct 22 00:00:00 EDT 2008}
}
  • Dissociative recombination of molecular ions with electrons is the most important neutralising process in plasmas cold enough to contain molecules. The basic features and principles describing recombination of diatomic molecular ions are now reasonably well characterised and understood. However, recombination of polyatomic ions is much less well understood. Over the last six years, experiments carried out at ion storage rings have shown that tri-atomic molecular ions tend to break up into three atoms upon recombination with free electrons. The question of how this break-up occurs has started to be investigated at ion storage rings using particle-imaging techniques. In this presentation,more » the imagine technique used in these experiments will be discussed together with results obtained from studies of H2O+, NH{sub 2}{sup +} and CH{sub 2}{sup +}. Finally, the use of this technique to study the dissociative recombination of more complex polyatomic ions, for example D{sub 5}O{sub 2}{sup +}, will also be discussed.« less
  • The cross section for dissociative recombination of vibrationally cold D{sub 3}{sup +} has been measured at the ion storage ring CRYRING. The rate constant at 300K, {alpha}=2.7{times}10{sup {minus}8} cm {sup 3} s{sup {minus}1} , is a factor of 4.3 smaller than the corresponding value for H{sub 3}{sup +} measured earlier in CRYRING. An electric field of 30V/cm was introduced in the electron-ion interaction region. This had no measurable effect on the dissociative recombination cross section. This suggests that the cross sections measured in storage rings for H{sub 3}{sup +} and its isotopic variants can be directly compared with theoretical resultsmore » once such results become available. {copyright} {ital 1997} {ital The American Physical Society}« less
  • Femtosecond time-resolved soft x-ray transient absorption spectroscopy based on a high-order harmonic generation source is used to investigate the dissociative ionization of CH{sub 2}Br{sub 2} induced by 800 nm strong-field irradiation. At moderate peak intensities (2.0 x 10{sup 14} W/cm{sup 2}), strong-field ionization is accompanied by ultrafast C-Br bond dissociation, producing both neutral Br ({sup 2}P{sub 3/2}) and Br* ({sup 2}P{sub 1/2}) atoms together with the CH{sub 2}Br{sup +} fragment ion. The measured rise times for Br and Br* are 130 {+-} 22 fs and 74 {+-} 10 fs, respectively. The atomic bromine quantum state distribution shows that the Br/Br*more » population ratio is 8.1 {+-} 3.8 and that the Br {sup 2}P{sub 3/2} state is not aligned. The observed product distribution and the timescales of the photofragment appearances suggest that multiple field-dressed potential energy surfaces are involved in the dissociative ionization process. In addition, the transient absorption spectrum of CH{sub 2}Br{sub 2}{sup +} suggests that the alignment of the molecule relative to the polarization axis of the strong-field ionizing pulse determines the electronic symmetry of the resulting ion; alignment of the Br-Br, H-H, and C{sub 2} axis of the molecule along the polarization axis results in the production of the ion {tilde X}({sup 2}B{sub 2}), {tilde B}({sup 2}B{sub 1}) and {tilde C}({sup 2}A{sub 1}) states, respectively. At higher peak intensities (6.2 x 10{sup 14} W/cm{sup 2}), CH{sub 2}Br{sub 2}{sup +} undergoes sequential ionization to form the metastable CH{sub 2}Br{sub 2}{sup 2+} dication. These results demonstrate the potential of core-level probing with high-order harmonic transient absorption spectroscopy for studying ultrafast molecular dynamics.« less
  • We present the application of ultrafast time- and mass-resolved ion yield laser spectroscopy in conjunction with ab initio electronic structure calculations to track molecular excited-state dynamics. We discuss how molecular fragment ions can be associated with conformations the molecule assumes during its relaxation, and how various features of the pump-probe signal for those fragments can be used to infer details of the excited state dynamics. We present results for radiationless relaxation in DNA and RNA bases adenine, cytosine, and uracil in the gas phase, pumped near a one-photon resonance transition to an excited state, and probed via strong-field near-IR dissociativemore » ionization.« less
  • Correlation images of the symmetric six-electron Coulomb-explosion channel of CO{sub 2} were used to isolate specific geometries (linear and bent) for angular-resolved analysis of the Coulomb-explosion energy in the framework of both the critical radius R{sub c} and dynamic screening models. We show that it is possible to connect the R{sub c} and screening pictures through a single parameter, a charge defect {sigma}, which depends on the charge state and the ratio between R{sub c} and the equilibrium bond length. Our data show that R{sub c} and hence {sigma} are slow varying functions of bond angle between 145 deg. andmore » 180 deg. with R{sub c}{approx}4 a.u. and {sigma}{approx}0.5 for the symmetric six-electron channel of CO{sub 2}. In the R{sub c} picture, the experimental value for R{sub c} is consistent with a theoretical value associated with CO{sub 2}{sup 3+}, which is considerably smaller than that associated with CO{sub 2}{sup +}({approx}6 a.u.)« less