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Full-Text Articles in Physical Sciences and Mathematics
Polarization And Ellipticity Of High-Order Harmonics From Aligned Molecules Generated By Linearly Polarized Intense Laser Pulses, Anh-Thu Le, R. R. Lucchese, C. D. Lin
Polarization And Ellipticity Of High-Order Harmonics From Aligned Molecules Generated By Linearly Polarized Intense Laser Pulses, Anh-Thu Le, R. R. Lucchese, C. D. Lin
Physics Faculty Research & Creative Works
We present theoretical calculations for polarization and ellipticity of high-order harmonics from aligned N₂, CO₂, and O₂ molecules generated by linearly polarized lasers. Within the rescattering model, the two polarization amplitudes of the harmonics are determined by the photo-recombination amplitudes for photons emitted with polarization parallel or perpendicular to the direction of the same returning electron wave packet. Our results show clear species-dependent polarization states, in excellent agreement with experiments. We further note that the measured polarization ellipse of the harmonic furnishes the needed parameters for a "complete" experiment in molecules.
Theoretical Study Of Photoelectron Angular Distributions In Single-Photon Ionization Of Aligned N₂ And Co₂, Cheng Jin, Anh-Thu Le, Song-Feng Zhao, R. R. Lucchese, C. D. Lin
Theoretical Study Of Photoelectron Angular Distributions In Single-Photon Ionization Of Aligned N₂ And Co₂, Cheng Jin, Anh-Thu Le, Song-Feng Zhao, R. R. Lucchese, C. D. Lin
Physics Faculty Research & Creative Works
We calculate photoelectron angular distributions (PADs) resulting from single-photon (43 eV) ionization of molecules that have been transiently aligned with a short laser pulse. The total ionization cross sections of N₂ and CO₂ vs the time delay between the aligning laser pulse and the soft x-ray photon are calculated and compared to experimental results reported by I. Thomann et al. [J. Phys. Chem. A 112, 9382 (2008)]. We present the PADs from these aligned molecules in the laboratory frame which can be compared directly with future experiments from aligned N₂ and CO₂. The alignment dependence of single-photon ionization, multiphoton ionization, …
Quantitative Rescattering Theory For High-Order Harmonic Generation From Molecules, Anh-Thu Le, R. R. Lucchese, S. Tonzani, Toru Morishita, C. D. Lin
Quantitative Rescattering Theory For High-Order Harmonic Generation From Molecules, Anh-Thu Le, R. R. Lucchese, S. Tonzani, Toru Morishita, C. D. Lin
Physics Faculty Research & Creative Works
The quantitative rescattering theory (QRS) for high-order harmonic generation (HHG) by intense laser pulses is presented. According to the QRS, HHG spectra can be expressed as a product of a returning electron wave packet and the photorecombination differential cross section of the laser-free continuum electron back to the initial bound state. We show that the shape of the returning electron wave packet is determined mostly by the laser. The returning electron wave packets can be obtained from the strong-field approximation or from the solution of the time-dependent Schrödinger equation (TDSE) for a reference atom. The validity of the QRS is …
Probing Molecular Frame Photoionization Via Laser Generated High-Order Harmonics From Aligned Molecules, Anh-Thu Le, R. R. Lucchese, M. T. Lee, C. D. Lin
Probing Molecular Frame Photoionization Via Laser Generated High-Order Harmonics From Aligned Molecules, Anh-Thu Le, R. R. Lucchese, M. T. Lee, C. D. Lin
Physics Faculty Research & Creative Works
Present experiments cannot measure molecular frame photoelectron angular distributions (MFPAD) for ionization from the outermost valence orbitals of molecules. We show that the details of MFPAD can be retrieved with high-order harmonics generated by infrared lasers from aligned molecules. Using accurately calculated photoionization transition dipole moments for fixed-in-space molecules, we show that the dependence of the magnitude and phase of the high-order harmonics on the alignment angle of the molecules observed in recent experiments can be quantitatively reproduced. This result provides the needed theoretical basis for ultrafast dynamic chemical imaging using infrared laser pulses.