Intense-field molecular ionization, for extended test of theory

• Applicant: Professor Dr. Hanspeter Helm
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2006 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 32438436

• Final Report Year: 2011

Final Report Abstract

1. We have studied the strong-field ionization of molecular hydrogen covering the entire wavelength range from 300 to 800 nm at intensities from 5×1012 to 5×1014 W/cm2 at pulse durations of ≈100 fs. Angle resolved electron momentum distributions were recorded as well as absolute ionization yields. 2. A theoretical model was developed to predict the non-ponderomotive shift of the excited states of molecular hydrogen and their role as intermediate resonances in strong field ionization. The model serves to give quantitative predictions of angular distributions and is capable of identifying the dominant resonance contributions in strong-field ionization.

Publications

• Imaging electrons, ions, atoms and electromagnetic fields. Bose-Memorial Lecture, Univ. Calcutta, December 2006
  H. Helm
  
• Photoelectron Spectroscopy of H2. WE Heraeus Summer School Wittenberg, Oct. 2006
  T. Wilbois
  
• Electric field effects in Rydberg states of hydrogen molecules. Atomic Physics meeting, MPIPKS, Dresden, November 27, 2007
  H. Helm
  
• Molecular hydrogen in strong linearly polarised laser fields. DPG Spring Meeting, Düsseldorf, March 2007
  T. Wilbois and H. Helm
  
• Photoelectron spectroscopy of H2 in strong laser fields. LPHYS 2007 Leon, Mexico, August 2007
  T. Wilbois and H. Helm
  
• Angular resolved photoelectron spectra of H2 in strong fields at wavelengths between 400 and 1350 nm. DPG Spring Meeting Darmstadt, March 2008
  T. Wilbois and H. Helm
  
• On the complex momentum spectra of photoelectrons formed from H2 in a strong laser. Laser Physics 18, 579 (2008)
  T. Wilbois and H. Helm
  
• Imaging of electrons, molecules, and electromagnetic fields, Applications in Basic and Applied Sciences. Technical University of Isfahan, April 13, 2009
  H. Helm
  
• Imaging of electrons, molecules, and electromagnetic fields, Applications in Basic and Applied Sciences. University of Shiraz, April 14, 2009
  H. Helm
  
• Ionization dynamics of H2 in strong fields - Experiments at visible wavelengths and Construction of a novel spectrometer. DPG Spring Meeting 2009 Hamburg, March 2009
  T. Wilbois and H. Helm
  
• Imaging electrons formed in ionization and detachment. EU-Summer School ICONIC, May 17th, 2010
  H. Helm
  
• Nonponderomotive effects in multiphoton ionization of molecular hydrogen. Physical Review A 83, 053414 (2011)
  T. Wilbois and H. Helm