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Symmetry breaking by quantum coherence in single electron attachment

Nature Physics volume 14, pages 149–153 (2018)Cite this article

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Abstract

Quantum coherence-induced effects in atomic and molecular systems are the basis of several proposals for laser-based control of chemical reactions. So far, these rely on coherent photon beams inducing coherent reaction pathways that may interfere with one another, to achieve the desired outcome. This concept has been successfully exploited for removing the inversion symmetry in the dissociation of homonuclear diatomic molecules, but it remains to be seen if such quantum coherent effects can also be generated by the interaction of incoherent electrons with such molecules. Here we show that resonant electron attachment to H2 and the subsequent dissociation into H (n = 2) + H− is asymmetric about the inter-nuclear axis, whereas the asymmetry in D2 is far less pronounced. We explain this observation as due to attachment of a single electron resulting in a coherent superposition of two resonances of opposite parity. In addition to exemplifying a new quantum coherent process, our observation of coherent quantum dynamics involves the active participation of all three electrons and two nuclei, which could provide new tools for studying electron correlations as a means to control chemical processes, and demonstrates the role of coherent effects in electron-induced chemistry.

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Figure 1: Expected angular distribution of H− from H2.
Figure 2: Velocity slice images of H− from H2 and D− from D2 at different electron energies.
Figure 3: Schematic of the DA process at 14 eV in H2 and D2.
Figure 4: Simulated forward–backward asymmetry (η) of the angular distribution for H2 and D2.

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References

  1. Tichy, M. C., Mintert, F. & Buchleitner, A. Essential entanglement for atomic and molecular physics. J. Phys. B 44, 192001 (2011).

    Article  ADS  Google Scholar 

  2. Rice, S. A. Interfering for the good of a chemical reaction. Nature 409, 422–426 (2001).

    Article  ADS  Google Scholar 

  3. Rabitz, H., de Vivie-Riedle, R., Motzkus, M. & Kompa, K. Whither the future of controlling quantum phenomena? Science 288, 824–828 (2000).

    Article  ADS  Google Scholar 

  4. Shapiro, M. & Brumer, P. Coherent control of molecular dynamics. Rep. Prog. Phys. 66, 859–942 (2003).

    Article  ADS  Google Scholar 

  5. Sansone, G. et al. Electron localization following attosecond molecular photoionization. Nature 465, 763–766 (2010).

    Article  ADS  Google Scholar 

  6. Glover, S. C., Savin, D. W. & Jappsen, A.-K. Cosmological implications of the uncertainty in H− destruction rate coefficients. Astrophys. J. 640, 553–568 (2006).

    Article  ADS  Google Scholar 

  7. Kreckel, H. et al. Experimental results for H2 formation from H− and H and implications for first star formation. Science 329, 69–71 (2010).

    Article  ADS  Google Scholar 

  8. Field, D. H2 formation in space: a negative ion route? Astron. Astrophys. 362, 774–779 (2000).

    ADS  Google Scholar 

  9. Fantz, U., Reiter, D., Heger, B. & Coster, D. Hydrogen molecules in the diverter of ASDEX Upgrade. J. Nucl. Mater. 290–293, 367–373 (2001).

    Article  ADS  Google Scholar 

  10. Taccogna, F. et al. Plasma–neutral interaction in kinetic models for the divertor region. Contrib. Plasma Phys. 48, 147–152 (2008).

    Article  ADS  Google Scholar 

  11. O’ Malley, T. F. Theory of dissociative attachment. Phys. Rev. 150, 14–29 (1966).

    Article  ADS  Google Scholar 

  12. Van Brunt, R. J. & Keiffer, L. J. Angular distribution of O− from dissociative electron attachment to O2 . Phys. Rev. A 2, 1899–1905 (1970).

    Article  ADS  Google Scholar 

  13. Tronc, M., Fiquet-Fayard, F., Schermann, C. & Hall, R. I. Differential cross sections and angular distributions of H− from dissociative electron attachment to H2 between 3.75 eV and 13 eV. J. Phys. B 10, 305–321 (1977).

    Article  ADS  Google Scholar 

  14. Prabhudesai, V. S., Nandi, D. & Krishnakumar, E. On the presence of the 4Σu− resonance in dissociative electron attachment to O2 . J. Phys. B 39, L277–L283 (2006).

    Article  ADS  Google Scholar 

  15. Gope, K., Prabhudesai, V. S., Mason, N. J. & Krishnakumar, E. Probing the resonant states of Cl2 using velocity slice imaging. J. Phys. B 49, 015201 (2016).

    Article  ADS  Google Scholar 

  16. Krishnakumar, E., Denifl, S., Čadež, I., Markelj, S. & Mason, N. J. Dissociative electron attachment cross sections for H2 and D2 . Phys. Rev. Lett. 106, 243201 (2011).

    Article  ADS  Google Scholar 

  17. Čadež, I., Markelj, S., Rupnik, Z. & Pelicon, P. Processes with neutral hydrogen and deuterium molecules relevant to edge plasma in tokamaks. J. Phys. Conf. Ser. 133, 012029 (2008).

    Article  Google Scholar 

  18. Nandi, D., Prabhudesai, V. S., Krishnakumar, E. & Chatterjee, A. Velocity slice imaging for dissociative electron attachment. Rev. Sci. Instrum. 76, 053107 (2005).

    Article  ADS  Google Scholar 

  19. Schulz, G. J. Resonances in electron impact on diatomic molecules. Rev. Mod. Phys. 45, 423–487 (1973).

    Article  ADS  Google Scholar 

  20. Comer, J. & Read, F. H. Potential curves and symmetries of some resonant states of H2−. J. Phys. B 4, 368–388 (1971).

    Article  ADS  Google Scholar 

  21. Weingartshofer, A., Ehrhardt, H., Hermann, V. & Linder, F. Measurements of absolute cross sections for (e, H2) collision processes. Formation and decay of H2− resonances. Phys. Rev. A 2, 204–304 (1970).

    Article  ADS  Google Scholar 

  22. Tronc, M., Hall, R. I., Schermann, C. & Taylor, H. S. Interference in dissociative attachment cross sections of H2 around 14 eV. J. Phys. B 12, L279–L282 (1979).

    Article  ADS  Google Scholar 

  23. Celiberto, R., Janev, R. K., Wadehra, J. M. & Tennyson, J. Dissociative electron attachment to vibrationally excited H2 molecules involving the 2Σg+ resonant Rydberg electronic state. Chem. Phys. 398, 206–213 (2012).

    Article  Google Scholar 

  24. Stibbe, D. T. & Tennyson, J. Electron–H2 scattering resonances as a function of bond length. J. Phys. B 31, 815–844 (1998).

    Article  ADS  Google Scholar 

  25. Sharp, T. E. Potential-energy curves for molecular hydrogen and its ions. At. Data 2, 119–169 (1971).

    Article  ADS  Google Scholar 

  26. Martin, F. et al. Single-photon induced symmetry breaking of H2 dissociation. Science 315, 629–633 (2007).

    Article  ADS  Google Scholar 

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Acknowledgements

We thank B. Nestmann and Y. Sajeev for useful discussions. E.K. acknowledges a Marie Curie Fellowship during the course of the measurements and E.K. and V.S.P. acknowledge the Department of Atomic Energy, India for financial support during the course of the work. N.J.M. recognizes support from the European Union Framework 7 programme LASSIE Marie Curie ITN Grant Agreement 238258 and VAMDC INFRA-2008-1.2.2 Scientific Data Infrastructure. Grant Agreement number: 239108.

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Authors and Affiliations

  1. Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005, India

    E. Krishnakumar & Vaibhav S. Prabhudesai

  2. Open University, Walton Hall, Milton Keynes MK7 6AA, UK

    Nigel J. Mason

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  1. E. Krishnakumar
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  2. Vaibhav S. Prabhudesai
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Contributions

E.K. and N.J.M. planned the research. E.K. built the experiment with help from N.J.M. and carried out the measurements. V.S.P. carried out the simulations and V.S.P. and E.K. interpreted the results. E.K. and V.S.P. prepared the manuscript.

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Correspondence to E. Krishnakumar.

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The authors declare no competing financial interests.

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Krishnakumar, E., Prabhudesai, V. & Mason, N. Symmetry breaking by quantum coherence in single electron attachment. Nat. Phys. 14, 149–153 (2018). https://doi.org/10.1038/nphys4289

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