Eric Suraud

Time-dependent density-functional theory with a self-interaction correction.

We discuss an implementation of the self-interaction correction for the local-density approximation to time-dependent density-functional theory. A variational formulation is given, taking care of the necessary constraints. A manageable and transparent propagation scheme using two sets of wave functions is proposed and applied to laser excitation with subsequent ionization of a dimer molecule.

Koopmans' condition in self-interaction corrected density functional theory

We investigate from a practitioners point of view the computation of the ionization potential (IP) within density-functional theory (DFT). DFT with (semi)local energy-density functionals is plagued by a self-interaction error which hampers the computation of the IP from the single-particle energy of the highest occupied molecular orbital (HOMO). The problem may be cured by a self-interaction correction (SIC) for which there exist various approximate treatments. We compare the performance of the SIC proposed by Perdew and Zunger with the very simple average-density SIC (ADSIC) for a large variety of atoms and molecules up to larger systems such as carbon rings and chains. Both approaches to the SIC provide a large improvement to the quality of the IP if calculated from the HOMO level. The surprising result is that the simple ADSIC performs even better than the original Perdew-Zunger SIC in the majority of the studied cases.

On the exact treatment of time-dependent self-interaction correction

We present a new formulation of the time-dependent self-interaction correction (TDSIC). It is derived variationally obeying explicitly the constraints on orthonormality of the occupied single-particle orbitals. The thus emerging rather involved symmetry condition amongst the orbitals is dealt with using two separate sets of (occupied) single-particle wavefunctions, related by a unitary transformation. The double-set TDSIC scheme is well suited for numerical implementation. We present results for laser-excited dynamics in a 1D model for a molecule and in fully fledged 3D calculations.

Density functional theory and Kohn-Sham scheme for self-bound systems

We demonstrate how the separation of the total energy of a self-bound system into a functional of the internal one-body Fermionic density and a function of an arbitrary wave vector describing the center-of-mass kinetic energy can be used to set up an internal Kohn-Sham scheme.

Simple Models of Many-Fermion Systems

The Variety of Finite Fermion Systems and Their Basic Properties.- The Fermi-Gas Model.- Particles in an External Field.- Approaches Based on Model Spaces.- Hartree-Fock.- Density Functional Theory.- Quasispin Models.- Excitation Spectra.- Coherent Two-Body Correlations.- Conclusions.

Dynamics of cluster deposition on Ar surface

Abstract. Using a combined quantum mechanical/classical method, we study thendynamics of deposition of small Na clusters on Ar(001) surface. Wenwork out basic mechanisms by systematic variation of substratenactivity, impact energy, cluster orientations, cluster sizes, andncharges. The soft Ar material is found to serve as an extremelynefficient shock absorber which provides cluster capture in a broadnrange of impact energies. Reflection is only observed in combinationnwith destruction of the substrate. The kinetic energy of thenimpinging cluster is rapidly transfered at first impact. Thendistribution of the collision energy over the substrate proceeds verynfast with velocity of sound. The full thermalization of ionic andnatomic energies goes at a much slower pace with times of several ps.nCharged clusters are found to have a much stronger interfaceninteraction and thus get in significantly closer contact with thensurface. n

Frequency dependence of level depletion in Na clusters and in C2H4

In the framework of time-dependent density-functional theory, we study electron emission from Na clusters and the C2H4 molecule as induced by irradiation with an intense pulse. The collision of a charged projectile with C2H4 is also explored for comparison. We look in particular at the level depletion, i.e. the electron loss in each single-electron level separately. It is found that the distribution of electron loss depends sensitively on the photon frequency. Frequencies close to visible light remove electrons exclusively from the vicinity of the Fermi surface while light in the higher UV range (up to 20 eV for Na clusters and up to 136 eV for C2H4) depletes all levels, about equally strong, down to the deepest bound valence state.

The Generalized SIC-OEP formalism and the Generalized SIC-Slater approximation (stationary and time-dependent cases).

We present a generalized formulation of the Optimized Effective Potential (OEP) approach to the Self Interaction Correction (SIC) problem in Time Dependent (TD) Density Functional Theory (DFT). The formulation relies on the introduction of a double set of single electron orbitals. It allows the derivation of a generalized Slater approximation to the full OEP formulation, which extends the domain of validity of the standard Slater approximation. We discuss both formal aspects and practical applications of the new formalism and give illustrations in cluster and molecules. The new formalism provides a valuable ansatz to more elaborate (and computationally very demanding) full TD OEP and full TD SIC calculations especially in the linear domain.

Exploration of dynamical regimes of irradiated small protonated water clusters

We explore from a theoretical perspective the dynamical response of small water clusters, (H2O)nH3O+ with n=1,2,3, to a short laser pulse for various frequencies, from infrared (IR) to ultra-violet (UV) and intensities (from

Polarizabilities as a test of localized approximations to the self-interaction correction

6times10^{13}~{rm W/cm}^2