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Title: Effect of an improved molecular potential on strong-field tunneling ionization of molecules

Abstract

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 {alpha}) model, the binding energies of outer shells of molecules are significantly improved. However, we show that the tunneling ionization rates from the LB {alpha} do not differ much from the earlier calculations [Phys. Rev. A 81, 033423 (2010)], in which the local correlation potential was neglected.

Authors:
;  [1];  [2]; ;  [1]
  1. J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, Kansas 66506-2604 (United States)
  2. (China)
Publication Date:
OSTI Identifier:
21450672
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 82; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.82.035402; (c) 2010 The American Physical Society
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; BINDING ENERGY; ELECTRIC FIELDS; ELECTRON CORRELATION; ELECTRONS; IONIZATION; MOLECULES; POTENTIALS; TUNNEL EFFECT; CORRELATIONS; ELEMENTARY PARTICLES; ENERGY; FERMIONS; LEPTONS

Citation Formats

Zhao Songfeng, Jin Cheng, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou, Gansu 730070, Le, Anh-Thu, and Lin, C. D. Effect of an improved molecular potential on strong-field tunneling ionization of molecules. United States: N. p., 2010. Web. doi:10.1103/PHYSREVA.82.035402.
Zhao Songfeng, Jin Cheng, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou, Gansu 730070, Le, Anh-Thu, & Lin, C. D. Effect of an improved molecular potential on strong-field tunneling ionization of molecules. United States. doi:10.1103/PHYSREVA.82.035402.
Zhao Songfeng, Jin Cheng, College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou, Gansu 730070, Le, Anh-Thu, and Lin, C. D. Wed . "Effect of an improved molecular potential on strong-field tunneling ionization of molecules". United States. doi:10.1103/PHYSREVA.82.035402.
@article{osti_21450672,
title = {Effect of an improved molecular potential on strong-field tunneling ionization of molecules},
author = {Zhao Songfeng and Jin Cheng and College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou, Gansu 730070 and Le, Anh-Thu and Lin, C. D.},
abstractNote = {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 {alpha}) model, the binding energies of outer shells of molecules are significantly improved. However, we show that the tunneling ionization rates from the LB {alpha} do not differ much from the earlier calculations [Phys. Rev. A 81, 033423 (2010)], in which the local correlation potential was neglected.},
doi = {10.1103/PHYSREVA.82.035402},
journal = {Physical Review. A},
number = 3,
volume = 82,
place = {United States},
year = {Wed Sep 15 00:00:00 EDT 2010},
month = {Wed Sep 15 00:00:00 EDT 2010}
}
  • We present a detailed comparison of strong-field ionization of diatomic molecules and their companion atoms with nearly equal ionization potentials. We perform calculations in the length and velocity gauge formulations of the molecular strong-field approximation and with the molecular tunneling theory, and in both cases we consider effects of nuclear motion. A comparison of our results with experimental data shows that the length gauge strong-field approximation gives the most reliable predictions.
  • 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. Withmore » the new parameters we examine the alignment-dependent tunneling ionization probabilities for several molecules and compare with other calculations and with recent measurements, including ionization from inner molecular orbitals.« less
  • No abstract prepared.
  • A model based on the strong-field and Born-Oppenheimer approximations qualitatively describes the distribution over vibrational states formed in a diatomic molecular ion following ionization of the neutral molecule by intense laser pulses. Good agreement is found with a recent experiment [X. Urbain et al., Phys. Rev. Lett. 92, 163004 (2004)]. In particular, the observed deviation from a Franck-Condon-like distribution is reproduced. Additionally, we demonstrate control of the vibrational distribution by a variation of the peak intensity or a change of frequency of the laser pulse.
  • The molecular strong-field approximation (MSFA), which includes dressing of the molecular bound state, is introduced and applied to above-threshold ionization of heteronuclear diatomic molecules. Expressions for the laser-induced molecular dipole and polarizability as functions of the laser parameters (intensity and frequency) and molecular parameters [molecular orientation, dipole, and parallel and perpendicular polarizabilities of the highest occupied molecular orbital (HOMO)] are presented. Our previous MSFA theory, which incorporates the rescattering effects, is generalized from homonuclear to heteronuclear diatomic molecules. Angle- and energy-resolved high-order above-threshold ionization spectra of oriented heteronuclear diatomic molecules, exemplified by the carbon monoxide (CO) molecule, exhibit pronounced minima,more » which can be related to the shape of their HOMO-electron-density distribution. For the CO molecule we have found an analytical condition for the positions of these minima. We have also shown that the effect of the dressing of the HOMO is twofold: (i) the laser-induced Stark shift decreases the ionization yield and (ii) the laser-induced time-dependent dipole and polarizability change the oscillatory structure of the spectra.« less