AMO Seminar - Junliang XU (Kansas State University) "Dynamic Imaging of a Molecule using Intense Laser Pulses"

A headshot of Junliang XU with a grey background.
December 16, 2011
1:00PM - 2:00PM
4138 PRB

Date Range
2011-12-16 13:00:00 2011-12-16 14:00:00 AMO Seminar - Junliang XU (Kansas State University) "Dynamic Imaging of a Molecule using Intense Laser Pulses" Laser-induced electron diffraction (LIED) is a new way proposed in recent years to image ultrafast dynamic systems.  In this talk, I will present our analysis of experimental LIED data with MIR lasers for N2 and O2. The N-N bond length retrieved from the data agrees with that for N2 to within 5%. For O2 the retrieved bond length is consistently much smaller than the known O-O bond length 1.21Å. Instead, it is much closer to the bond length of O2+, 1.12Å. We interpret this result in terms of bond relaxation of O2 following tunneling ionization. O2+ has a vibrational period of 17 fs while the returning time for a 2000 nm laser is about ~5-6 fs, thus allowing the two O atoms to relax from its initial separation of 1.21 Å to the new separation of 1.12 Å of O2+. This investigation establishes a foundation for this novel method for spatio-temporal imaging of gas-phase molecules. 4138 PRB America/New_York public

Laser-induced electron diffraction (LIED) is a new way proposed in recent years to image ultrafast dynamic systems.  In this talk, I will present our analysis of experimental LIED data with MIR lasers for N2 and O2. The N-N bond length retrieved from the data agrees with that for N2 to within 5%. For O2 the retrieved bond length is consistently much smaller than the known O-O bond length 1.21Å. Instead, it is much closer to the bond length of O2+, 1.12Å. We interpret this result in terms of bond relaxation of O2 following tunneling ionization. O2+ has a vibrational period of 17 fs while the returning time for a 2000 nm laser is about ~5-6 fs, thus allowing the two O atoms to relax from its initial separation of 1.21 Å to the new separation of 1.12 Å of O2+. This investigation establishes a foundation for this novel method for spatio-temporal imaging of gas-phase molecules.