Studies of Ultrafast Molecular processes by Multiparticle Imaging Techniques

• Applicant: Professor Dr. Reinhard Dörner
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2013 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 242361864

• Final Report Year: 2019

Final Report Abstract

One of the key results was the successful imaging of electrons emitted from a breaking bond upon ultrafast dissociation of HCl. In this experiment which was jointly performed analyzed and interpreted by the Frankfurt and the Paris team we could show that the HCl fragments rapidly upon excitation. During the dissociation the Auger decay occurs and for one of the decay channels the angular distribution of the Auger electron evolves as function of internuclear distance from a molecular distribution oriented along the bond axis to a shape resembling an atomic p-Orbital which is oriented perpendicular to the bond axis. A similar experiment has been performed on CH3Cl. A further experiment on Auger electron emission from fast dissociation from excited O2 turned out to be very challenging and instead of studying the localization of an orbital in O2 we conducted a successful experiment on Ne2. There we found that for certain regimes of the kinetic energy of the fragments the electron emission from Ne(2p) occurs coherently at both centers, i.e. a seemingly localized atomic orbital still produces interference. Further experiments on localization in CF4 were also published. Another joint project of the French and Frankfurt team was ultrafast dissociation of CH2BrCl upon excitation of the Br 3d orbital. In this work we could show, that the ultrafast dissociation induces a slingshot type internal rotation of the CH2Br. In summary we could show, that multicoincidence experiments on ultrafast dissociation is a powerful tool to investigate the time evolution of orbitals and the time evolution of molecular rearrangement. We also could show how a seemingly localized electronic orbital still leads to coherent electron emission from two sites in a dimer.

Publications

• Auger decay and subsequent fragmentation pathways of ethylene following K-shell ionization. Phys. Rev. A, 92 (2015) 013408
  B. Gaire, D. J. Haxton, F. P. Sturm, J. Williams, A. Gatton, I. Bocharova, N. Gehrken, M. Schöffler, H. Gassert, S. Zeller, J. Voigtsberger, T. Jahnke, M. Zohrabi, D. Reedy, C. Nook, A. L. Landers, A. Belkacem, C. L. Cocke, I. Ben-Itzhak, R. Dörner, and Th. Weber
  
• Elektronenemission aus dissoziierenden Molekülen. Dissertation, Frankfurt (2015)
  Hendrik Sann
  
• Delocalization of a Vacancy across Two Neon Atoms Bound by the van der Waals Force. Phys. Rev. Lett., 117 (2016) 263001
  H. Sann, C. Schober, A. Mhamdi, F. Trinter, C. Müller, S. K. Semenov, M. Stener, M. Waitz, T. Bauer, R. Wallauer, C. Goihl, J. Titze, F. Afaneh, L. Ph. H. Schmidt, M. Kunitski, H. Schmidt-Böcking, Ph. V. Demekhin, N. A. Cherepkov, M. S. Schöffler, T. Jahnke, R. Dörner
  
• Imaging the Temporal Evolution of Molecular Orbitals during Ultrafast Dissociation. Phys. Rev. Lett., 117 (2016) 243002
  H. Sann, T. Havermeier, C. Müller, H.-K. Kim, F. Trinter, M. Waitz, J. Voigtsberger, F. Sturm, T. Bauer, R. Wallauer, D. Schneider, M. Weller, C. Goihl, J. Tross, K. Cole, J. Wu, M. S. Schöffler, H. Schmidt-Böcking, T. Jahnke, M. Simon, R. Dörner
  
• Born in weak fields: below-threshold photoelectron dynamics. J. Phys. B-At. Mol. Opt., 50 (2017) 034002
  J. B. Williams, U. Saalmann, F. Trinter, M. S. Schöffler, M. Weller, P. Burzynski, C. Goihl, K. Henrichs, C. Janke, B. Griffin, G. Kastirke, J. Neff, M. Pitzer, M. Waitz, Y. Yang, G. Schiwietz, S. Zeller, T. Jahnke, R. Dörner
  
• Unambiguous observation of F-atom core-hole localization in CF4 through body-frame photoelectron angular distributions. Phys. Rev. A, 95 (2017) 011401(R)
  C. W. McCurdy, T. N. Rescigno, C. S. Trevisan, R. R. Lucchese, B. Gaire, A. Menssen, M. S. Schöffler, A. Gatton, J. Neff, P. M. Stammer, J. Rist, S. Eckart, B. Berry, T. Severt, J. Sartor, A. Moradmand, T. Jahnke, A. L. Landers, J. B. Williams, I. Ben-Itzhak, R. Dörner, A. Belkacem, Th. Weber
  
• Dissociation dynamics of the water dication following one-photon double ionization. II. Experiment. Phys. Rev. A, 98 (2018) 053430
  D. Reedy, J. B. Williams, B. Gaire, A. Gatton, M. Weller, A. Menssen, T. Bauer, K. Henrichs, Ph. Burzynski, B. Berry, Z. L. Streeter, J. Sartor, I. Ben-Itzhak, T. Jahnke, R. Dörner, Th. Weber, A. L. Landers