Nonlinear Time-Dependent Density Functional Theory Studies of Ionization in CO2 and N2 by Intense Laser Pulses and Molecular Orbital Reconstruction

Time-dependent density functional theory, TDDFT, studies of the ionization of CO2 and N2, by intense laser pulses peak intensities (3.50×1014, 1.40×1015, 2.99×1015 and 5.59×1015 W/cm2) at 800 nm (ω = 0.0584 a.u.) are presented in the nonlinear nonpertubative regime using the LB94 potential which reproduces the ionization potential of our systems more accurately, without significant increase in computational costs over a local-density approximation. Special emphasis is placed on elucidating molecular orbital (MO) orientation and various peak intensities effects on the ionization processes. The results reveal that molecular orbital ionizations are strongly sensitive to their symmetry (MO shape), the induced dipole coupling between molecular orbitals, and the laser intensities. Notably, we found that with a proper choice of the laser intensity (3.5×1014 W/cm2), the sensitivity is strong enough so that the nature and symmetry of the highest occupied molecular orbital can be directly probed and visualized from the angular dependence of laser induced ionization. At higher intensities, ionization is found to occur also from inner orbitals, thus complicating imaging of simple orbitals.

[1]  Axel D. Becke,et al.  Density‐functional thermochemistry. IV. A new dynamical correlation functional and implications for exact‐exchange mixing , 1996 .

[2]  P. Hohenberg,et al.  Inhomogeneous Electron Gas , 1964 .

[3]  S. H. Vosko,et al.  Accurate spin-dependent electron liquid correlation energies for local spin density calculations: a critical analysis , 1980 .

[4]  A. Zunger,et al.  Self-interaction correction to density-functional approximations for many-electron systems , 1981 .

[5]  Weitao Yang,et al.  A challenge for density functionals: Self-interaction error increases for systems with a noninteger number of electrons , 1998 .

[6]  E. Gross,et al.  Time-dependent density functional theory. , 2004, Annual review of physical chemistry.

[7]  R. S. Mulliken.  Molecular Orbital Method and Molecular Ionization Potentials , 1948 .

[8]  M. Stener,et al.  Time-dependent density functional calculations of molecular photoionization cross sections: N2 and PH3 , 2000 .

[9]  Krieger,et al.  Systematic approximations to the optimized effective potential: Application to orbital-density-functional theory. , 1992, Physical review. A, Atomic, molecular, and optical physics.

[10]  R. Leeuwen,et al.  Exchange-correlation potential with correct asymptotic behavior. , 1994, Physical review. A, Atomic, molecular, and optical physics.

[11]  L. Kronik,et al.  Orbital-dependent density functionals: Theory and applications , 2008 .

[12]  A. Bandrauk,et al.  High-order harmonic generation from two-center molecules: Time-profile analysis of nuclear contributions , 2004 .

[13]  T. Koopmans,et al.  Über die Zuordnung von Wellenfunktionen und Eigenwerten zu den Einzelnen Elektronen Eines Atoms , 1934 .

[14]  U. Kleineberg,et al.  Atomic transient recorder , 2004, Nature.

[15]  J. Janak,et al.  Proof that ? E /? n i =e in density-functional theory , 1978 .

[16]  Filipp Furche,et al.  On the density matrix based approach to time-dependent density functional response theory , 2001 .

[17]  S. Chu,et al.  Role of the electronic structure and multielectron responses in ionization mechanisms of diatomic molecules in intense short-pulse lasers: An all-electron ab initio study , 2004 .

[18]  David A. Dixon,et al.  Ab Initio Prediction of the Activation Energy for the Abstraction of a Hydrogen Atom from Methane by Chlorine Atom , 1994 .

[19]  J. Levesque,et al.  Tomographic imaging of molecular orbitals , 2004, Nature.

[20]  Mark E. Casida,et al.  Time-Dependent Density Functional Response Theory of Molecular Systems: Theory, Computational Methods, and Functionals , 1996 .

[21]  E. Gross,et al.  Density-Functional Theory for Time-Dependent Systems , 1984 .

[22]  A. Becke.  Density-functional thermochemistry. V. Systematic optimization of exchange-correlation functionals , 1997 .

[23]  C. Lin,et al.  Effects of orbital symmetries in dissociative ionization of molecules by few-cycle laser pulses , 2005 .

[24]  H. Appel,et al.  octopus: a tool for the application of time‐dependent density functional theory , 2006 .

[25]  R. Hoffmann,et al.  What Do the Kohn−Sham Orbitals and Eigenvalues Mean? , 1999 .

[26]  Hong Jiang,et al.  Absorbing Boundary Conditions for the Schrödinger Equation , 1999, SIAM J. Sci. Comput..

[27]  Naoto Umezawa,et al.  Explicit density-functional exchange potential with correct asymptotic behavior , 2006 .

[28]  C. Ullrich,et al.  Asymmetry of above-threshold ionization of metal clusters in two-color laser fields: A time-dependent density-functional study , 2004 .

[29]  Martins,et al.  Efficient pseudopotentials for plane-wave calculations. , 1991, Physical review. B, Condensed matter.

[30]  F. Krausz,et al.  Intense few-cycle laser fields: Frontiers of nonlinear optics , 2000 .

[31]  Parr,et al.  Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. , 1988, Physical review. B, Condensed matter.

[32]  G. Iafrate,et al.  Self-consistent calculations of atomic properties using self-interaction-free exchange-only Kohn-Sham potentials. , 1993, Physical review. A, Atomic, molecular, and optical physics.

[33]  E. Gross,et al.  The optimized effective potential method of density functional theory: Applications to atomic and molecular systems , 1997 .

[34]  J. Martins,et al.  A straightforward method for generating soft transferable pseudopotentials , 1990 .

[35]  J. D. Talman,et al.  Optimized effective atomic central potential , 1976 .

[36]  Henrik Stapelfeldt,et al.  Colloquium: Aligning molecules with strong laser pulses , 2003 .

[37]  Jeffrey A. Nichols,et al.  The optimized effective potential and the self-interaction correction in density functional theory: Application to molecules , 2000 .

[38]  G. Herzberg,et al.  Molecular Spectra and Molecular Structure , 1992 .

[39]  Jackson,et al.  Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation. , 1992, Physical review. B, Condensed matter.

[40]  A. Banerjee,et al.  Density-functional-theory calculations of the total energies, ionization potentials, and optical response properties with the van Leeuwen-Baerends potential , 1999 .

[41]  Density-functional theory using an optimized exchange-correlation potential , 1995, chem-ph/9504004.

[42]  H. Jiang,et al.  Piperidine–CO2–H2O molecular complex , 2003 .

[43]  Krieger,et al.  Construction and application of an accurate local spin-polarized Kohn-Sham potential with integer discontinuity: Exchange-only theory. , 1992, Physical review. A, Atomic, molecular, and optical physics.

[44]  J. Crank,et al.  A practical method for numerical evaluation of solutions of partial differential equations of the heat-conduction type , 1947 .

[45]  A. Bandrauk,et al.  Three-dimensional time-profile analysis of high-order harmonic generation in molecules: Nuclear interferences in H 2 + , 2005 .

[46]  R. T. Sharp,et al.  A Variational Approach to the Unipotential Many-Electron Problem , 1953 .

[47]  Kevin F. Lee,et al.  Direct measurement of the angular dependence of ionization for N2, O2, and CO2 in intense laser fields. , 2007, Physical review letters.

[48]  W. Kohn,et al.  Self-Consistent Equations Including Exchange and Correlation Effects , 1965 .