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Full-Text Articles in Physics
Effect Of An Improved Molecular Potential On Strong-Field Tunneling Ionization Of Molecules, Song-Feng Zhao, Cheng Jin, Anh-Thu Le, C. D. Lin
Effect Of An Improved Molecular Potential On Strong-Field Tunneling Ionization Of Molecules, Song-Feng Zhao, Cheng Jin, Anh-Thu Le, C. D. Lin
Physics Faculty Research & Creative Works
We study the effect of one-electron model potentials on the tunneling ionization rates of molecules in strong fields. By including electron correlation using the modified Leeuwen-Baerends (LB α) model, the binding energies of outer shells of molecules are significantly improved. However, we show that the tunneling ionization rates from the LB α do not differ much from the earlier calculations [Phys. Rev. A 81, 033423 (2010)], in which the local correlation potential was neglected.
Self-Imaging Of Molecules From Diffraction Spectra By Laser-Induced Rescattering Electrons, Junliang Xu, Zhangjin Chen, Anh-Thu Le, C. D. Lin
Self-Imaging Of Molecules From Diffraction Spectra By Laser-Induced Rescattering Electrons, Junliang Xu, Zhangjin Chen, Anh-Thu Le, C. D. Lin
Physics Faculty Research & Creative Works
We study high-energy angle-resolved photoelectron spectra of molecules in strong fields. In an oscillating laser electric field, electrons released earlier in the pulse may return to recollide with the target ion, in a process similar to scattering by laboratory prepared electrons. If midinfrared lasers are used, we show that the images generated by the returning electrons are similar to images observed in typical gas-phase electron diffraction (GED). These spectra can be used to retrieve the positions of atoms in a molecule as in GED. Since infrared laser pulses of durations of a few femtoseconds are already available today, the study …
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.
Herschel Images Of Ngc 6720: H2 Formation On Dust Grain, P. A. M. Van Hoof, G. C. Van De Steene, M. J. Barlow, K. M. Exter, B. Sibthorpe, T. Ueta, V. Peris, M. A. T. Groenewegen, J. A. D. L. Blommaert, M. Cohen, W. De Meester, Gary J. Ferland, W. K. Gear, H. L. Gomez, P. C. Hargrave, E. Huygen, R. J. Ivison, C. Jean, S. J. Leeks, T. L. Lim, G. Olofsson, E. T. Polehampton, S. Regibo, P. Royer, B. M. Swinyard, B. Vandenbussche, H. Van Winckel, C. Waelkens, H. J. Walker, R. Wesson
Herschel Images Of Ngc 6720: H2 Formation On Dust Grain, P. A. M. Van Hoof, G. C. Van De Steene, M. J. Barlow, K. M. Exter, B. Sibthorpe, T. Ueta, V. Peris, M. A. T. Groenewegen, J. A. D. L. Blommaert, M. Cohen, W. De Meester, Gary J. Ferland, W. K. Gear, H. L. Gomez, P. C. Hargrave, E. Huygen, R. J. Ivison, C. Jean, S. J. Leeks, T. L. Lim, G. Olofsson, E. T. Polehampton, S. Regibo, P. Royer, B. M. Swinyard, B. Vandenbussche, H. Van Winckel, C. Waelkens, H. J. Walker, R. Wesson
Physics and Astronomy Faculty Publications
Herschel PACS and SPIRE images have been obtained of NGC 6720 (the Ring nebula). This is an evolved planetary nebula with a central star that is currently on the cooling track, due to which the outer parts of the nebula are recombining. From the PACS and SPIRE images we conclude that there is a striking resemblance between the dust distribution and the H2 emission, which appears to be observational evidence that H2 forms on grain surfaces. We have developed a photoionization model of the nebula with the Cloudy code which we used to determine the physical conditions of …
Determination Of Structure Parameters In Strong-Field Tunneling Ionization Theory Of Molecules, Song-Feng Zhao, Cheng Jin, Anh-Thu Le, T. F. Jiang, C. D. Lin
Determination Of Structure Parameters In Strong-Field Tunneling Ionization Theory Of Molecules, Song-Feng Zhao, Cheng Jin, Anh-Thu Le, T. F. Jiang, C. D. Lin
Physics Faculty Research & Creative Works
In the strong field molecular tunneling ionization theory of Tong et al. [Phys. Rev. A 66, 033402 (2002)], the ionization rate depends on the asymptotic wave function of the molecular orbital from which the electron is removed. The orbital wave functions obtained from standard quantum chemistry packages in general are not good enough in the asymptotic region. Here we construct a one-electron model potential for several linear molecules using density functional theory. We show that the asymptotic wave function can be improved with an iteration method and after one iteration accurate asymptotic wave functions and structure parameters are determined. With …
Recent Theoretical Progress In Treating Electron Impact Ionization Of Molecules, Ola A. Al-Hagan, Chuangang Ning, Kate L. Nixon, Andrew James Murray, Christopher J. Colyer, Mark A. Stevenson, B. Lohmann, Don H. Madison
Recent Theoretical Progress In Treating Electron Impact Ionization Of Molecules, Ola A. Al-Hagan, Chuangang Ning, Kate L. Nixon, Andrew James Murray, Christopher J. Colyer, Mark A. Stevenson, B. Lohmann, Don H. Madison
Physics Faculty Research & Creative Works
(e,2e) ionization differential cross sections are presented for several molecules. We will compare experimental results with theoretical calculations using the molecular three body distorted wave (M3DW) approximations for H 2, N2, H2O and Formic Acid (FA) using better wave-function for the molecules than we had in previous works. Generally, good agreement is found between the M3DW approach and experiments.