References of "Remacle, Françoise"
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See detailLigand and Solvation Effects on the Electronic Properties of Au-55 Clusters: A Density Functional Theory Study
Periyasamy, Ganga ULg; Remacle, Françoise ULg

in Nano Letters (2009), 9(8), 3007-3011

The electronic properties of the neutral, positively and negatively charged bare Au-55, passivated Au-55(PH3)(12), Au-55(PH3)(12)Cl-6, and solvated Au-55(PH3)(12)Cl-6 54 H2O clusters are studied using ... [more ▼]

The electronic properties of the neutral, positively and negatively charged bare Au-55, passivated Au-55(PH3)(12), Au-55(PH3)(12)Cl-6, and solvated Au-55(PH3)(12)Cl-6 54 H2O clusters are studied using density functional theory. The presence of Cl atoms in the ligand shell favors a nonmetallic behavior while a more metallic behavior is induced by explicit solvation of Au-55(PH3)(12)Cl-6 with water molecules. The trends observed in the electronic properties upon ligation and solvation are in agreement with experimental studies, [less ▲]

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See detailCombined Mossbauer Spectral and Density Functional Theory Determination of the Magnetic Easy-Axis in Two High-Spin Iron(II) 2-Pyrazinecarboxylate Complexes
Long, G. J.; Tanase, S.; Remacle, Françoise ULg et al

in Inorganic Chemistry (2009), 48(17), 8173-8179

A combination of density functional theory (DFT) calculations and Mossbauer spectroscopy has been used to determine that the magnetic easy-axis is coincident with its crystallographic c-axis in [Fe(pca)(2 ... [more ▼]

A combination of density functional theory (DFT) calculations and Mossbauer spectroscopy has been used to determine that the magnetic easy-axis is coincident with its crystallographic c-axis in [Fe(pca)(2)(py)(2)]center dot py, where pac is the 2-pyrazinecarboxylate ligand. This easy-axis bisects the approximately axial O-Fe-O coordination axes of molecules adjacent to each other along the b-axis. In {[Fe(pca)(2)(H2O)]center dot H2O}(n) the easy magnetic axis is not coincident with any of its crystallographic axes nor with the Fe-O(water) coordination axis, but is coincident with one of the Fe center dot center dot center dot Fe axes in the crystal structure. The DFT calculations, which use the B3LYP functional and the 6-311 + +G(d,p) basis set, yield s-electron probability densities and electric field gradient tensors for the iron(II) ion that are in excellent agreement with the observed iron-57 Mossbauer spectral isomer shifts and quadrupole interactions. The gas phase results are very similar for calculations based either on the X-ray structures of the two complexes or on their optimized structures; the optimized structures indicate that the iron to ligand bond distances increase in the absence of any solid-state lattice interactions. The results of a normal coordinate vibrational mode analysis of the two optimized structures are compared with the observed infrared spectra. [less ▲]

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See detailElectrochemically Driven Sequential Machines: An Implementation of Copper Rotaxanes
Periyasamy, Ganga ULg; Collin, Jacques ULg; Sauvage, Jacques ULg et al

in Chemistry : A European Journal (2009), 15(6), 1310-1313

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See detailControlled full adder or subtractor by vibrational quantum computing
Bomble, L.; Lauvergnat, D.; Remacle, Françoise ULg et al

in Physical Review. A (2009), 80(2),

A controlled full addition or subtraction can be realized by a unitary transformation on a register of four qubits. The fourth qubit is then used as a control qubit to enforce the addition or the ... [more ▼]

A controlled full addition or subtraction can be realized by a unitary transformation on a register of four qubits. The fourth qubit is then used as a control qubit to enforce the addition or the subtraction of two binary digits and a carry or a borrow. The transformation can be decomposed into six elementary gates. The network differs from the adder network of four elementary gates by including two new controlled-NOT gates. The scheme is general and its implementation using vibrational computing has the advantage that the single global transformation that connects the inputs to the outputs can be driven in one step by a single laser shot. This decreases the time of operation and allows for a better use of the optical resources and for an improvement of the fidelity. The laser pulses are optimized by optimal control theory. [less ▲]

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See detailThe post-Born-Oppenheimer regime: dynamics of electronic motion in molecules by attosecond few-cycle spectroscopy
Muskatel, B. H.; Remacle, Françoise ULg; Levine, R. D.

in Physica Scripta (2009), 80(4),

Dynamics of electronic motion when the nuclei are clamped is discussed and shown to be always described as a superposition of adiabatic electronic states. These states are stationary when the nuclei are ... [more ▼]

Dynamics of electronic motion when the nuclei are clamped is discussed and shown to be always described as a superposition of adiabatic electronic states. These states are stationary when the nuclei are clamped but their superposition leads to multiply periodic motion where the natural frequencies are the differences in the energies of the adiabatic electronic states. When one or more of the frequencies are low and the atoms are allowed to move, the electronic rearrangement is commensurate with the motion of the nuclei. This is the usual breakdown of the Born-Oppenheimer approximation. But when the electronic frequencies are higher there is an electronic motion before the nuclei move. The motion can be demonstrated through expectation values such as the multipole moments of the charge distribution. Such superposition states will be excited when the laser pulse width in energy exceeds the spacings of the states. For low-lying valence excited or low Rydberg states this requires a femtosecond or shorter laser pulse. Since the carrier frequency has to be comparable to the excitation energy, the required laser pulses must span only a few cycles. [less ▲]

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See detailThe Elimination of Redundant Constraints in Surprisal Analysis of Unimolecular Dissociation and Other Endothermic Processes
Remacle, Françoise ULg; Levine, R. D.

in Journal of Physical Chemistry A (2009), 113(16), 4658-4664

It is well understood that energy rich polyatomic molecules do not dissociate promptly because the number, P, of their energy states far exceeds the number, N, of the decay channels. In the simplest RRK ... [more ▼]

It is well understood that energy rich polyatomic molecules do not dissociate promptly because the number, P, of their energy states far exceeds the number, N, of the decay channels. In the simplest RRK theory, the fraction N/P is the probability of dissociation. We discuss the distribution of the decay rates of maximal entropy and conclude that it is governed by at most N linearly independent constraints, N < P, or, more typically, N << P. This mathematical requirement already severely restricts the number of constraints. Beyond it however, on physical grounds, one constraint, or at most a few, may be dominant. We discuss why just one constraint, or a few but less than N, can be sufficient to describe the product state distribution. [less ▲]

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See detailReconfigurable Logic Devices on a Single Dopant Atom-Operation up to a Full Adder by Using Electrical Spectroscopy
Klein, M.; Lansbergen, G. P.; Mol, J. A. et al

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2009), 10(1), 162-173

A silicon field-effect transistor is operated as a logic circuit by electrically addressing the ground and excited electronic states of an embedded single dopant atom. Experimental results-complemented by ... [more ▼]

A silicon field-effect transistor is operated as a logic circuit by electrically addressing the ground and excited electronic states of an embedded single dopant atom. Experimental results-complemented by analytical and computational calculations-are presented. First, we show how a complete set of binary logic gates can be realized on the same hardware. Then, we show that these gates can be operated in parallel on the very some dopant up to the logic level of a full adder. To use the device not as a switch but as a full logic circuit, we make essential use of the excited electronic states of the dopant and of the ability to shift their energy by gating. The experimental ability to use two channels to measure the current flowing through the device and the conductance (dI/dV) allows for a robust reading of the output of the logic operations. [less ▲]

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See detailUltrafast vibrational spectroscopy and relaxation in polyatomic molecules: Potential for molecular parallel computing
Torres, E. A.; Kompa, K. L.; Remacle, Françoise ULg et al

in Chemical Physics (2008), 347(1-3), 531-545

The feasibility of controlled ultrafast pumping in the mid IR and the probe of the subsequent intramolecular dynamics is illustrated for vibrational excitation of the two metal carbonyls W(CO)(6) and Mn ... [more ▼]

The feasibility of controlled ultrafast pumping in the mid IR and the probe of the subsequent intramolecular dynamics is illustrated for vibrational excitation of the two metal carbonyls W(CO)(6) and Mn(CO)(5)Br in solution. Pumping and probing is performed by short, 130 fs, pulses centered at about 2000 cm(-1). Frequency resolved measurements of the time delayed probe pulse are performed. Measured two dimensional spectra are fitted by a kinetic scheme that models the vibrational dynamics. Fast relaxation is solvent induced with the solvent acting also as a heat bath. The (several) probe signals in the experiment can be thought of as the response of a finite state logic machine. This suggests that the molecular machine can act as an ultrafast (petaHertz) processor. The number of internal (memory) states of the machine is determined by the number of vibrational states in the kinetic scheme that can fit the observed relaxation. The number of outputs of the machine is the number of the several different available probe signals. It is shown that the machine is massively parallel because in each (sub ps) time step it produces an entire vector as an output and that each component of the output vector is, by itself, a transform over the input. Beyond that, the machine can produce a (finite number of) different output vectors in sequential time steps. (c) 2008 Elsevier BN. All rights reserved. [less ▲]

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See detailA density functional theory calculation of the electronic properties of several high-spin and low-spin iron(II) pyrazolylborate complexes
Remacle, Françoise ULg; Long, G. J.; Grandjean, Fernande ULg

in Inorganic Chemistry (2008), 47(10), 4005-4014

Density functional theory has been used to study the electronic spin-state properties of low-spin Fe[HB(PZ)(3)](2), lhigh-spin Fe[HB(3-MePZ)(3)](2), high-spin Fe[HB(3,5-Me(2)PZ)(3)](2), and high-spin Fe ... [more ▼]

Density functional theory has been used to study the electronic spin-state properties of low-spin Fe[HB(PZ)(3)](2), lhigh-spin Fe[HB(3-MePZ)(3)](2), high-spin Fe[HB(3,5-Me(2)PZ)(3)](2), and high-spin Fe[HB(3,4,5-Me(3)PZ)(3)](2) complexes that exhibit very different iron(II) electronic spin-sate crossover behaviors with changing temperature and pressure. Excellent agreement is obtained between the experimentally,observed Mossbauer-effect quadrupole splittings and isomer shifts of these complexes and those calculated with the B3LYP functional and various different basis sets for both the high-spin and low-spin states of iron(II). The calculations for Fe[HB(PZ)(3)](2) that use the LANL2DZ, 6-31++G(d,p), and 6-311++G(d,p) basis sets for iron all lead to very similar electric field gradients and thus quadrupole splittings. The initial calculations, which were based upon the known X-ray structures, were followed by structural optimization, an optimization that led to small increases in the Fe-N bond distances. Optimization led to at most trivial changes in the intraligand bond distances and angles. The importance of the 3-methy I-H center dot center dot center dot H-3-methyl nonbonded intramolecular interligand interactions in controlling the minimum Fe-N bond distances and determining the iron(II) spin state both in Fe[HB(3-Mepz)(3)](2) and in the related methyl-substituted complexes has been identified. [less ▲]

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See detailImplementation of simple logic gates on gold-ammonia bonding patterns in different charge states
Kryachko, Eugène ULg; Remacle, Françoise ULg

in Molecular Physics (2008), 106(2-4), 521-530

An approach is proposed for encoding the gold-ammonia bonding patterns on the conformational manifold of the Au-n(Z)-(NH3)(m), Z=0, +/- 1, clusters in order to implement simple unary and binary logic gate ... [more ▼]

An approach is proposed for encoding the gold-ammonia bonding patterns on the conformational manifold of the Au-n(Z)-(NH3)(m), Z=0, +/- 1, clusters in order to implement simple unary and binary logic gate operations. The gold-ammonia bonding patterns are governed by two different basic ingredients: the anchoring Au-N bond and the nonconventional N-H center dot center dot center dot Au hydrogen bond, and exhibit distinct characteristics as the charge of the cluster varies within Z = 0, +/- 1. The conformers of the small cluster, Au-Z-(NH3)(2), and of the nanometric size one, Au-20(Z), are chosen as illustrative examples. The dependence of the bonding patterns on the overall charge state of the cluster allows to implement the logic gates NOT, FAN-OUT, AND, NAND, OR, NOR, INH, XOR, and XNOR and to identify the outputs using an IR readout protocol. [less ▲]

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See detailComputational investigation and experimental considerations for the classical implementation of a full adder on SO2 by optical pump-probe schemes
Bomble, L.; Lavorel, B.; Remacle, Françoise ULg et al

in Journal of Chemical Physics (2008), 128(19),

Following the scheme recently proposed by Remacle and Levine [Phys. Rev. A 73, 033820 (2006)], we investigate the concrete implementation of a classical full adder on two electronic states ((X) over tilde ... [more ▼]

Following the scheme recently proposed by Remacle and Levine [Phys. Rev. A 73, 033820 (2006)], we investigate the concrete implementation of a classical full adder on two electronic states ((X) over tilde (1)A(1) and (C) over tilde B-1(2)) of the SO2 molecule by optical pump-probe laser pulses using intuitive and counterintuitive (stimulated Raman adiabatic passage) excitation schemes. The resources needed for providing the inputs and reading out are discussed, as well as the conditions for achieving robustness in both the intuitive and counterintuitive pump-dump sequences. The fidelity of the scheme is analyzed with respect to experimental noise and two kinds of perturbations: The coupling to the neighboring rovibrational states and a finite rotational temperature that leads to a mixture for the initial state. It is shown that the logic processing of a full addition cycle can be realistically experimentally implemented on a picosecond time scale while the readout takes a few nanoseconds. (c) 2008 American Institute of Physics. [less ▲]

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See detailPump and probe ultrafast electron dynamics in LiH: a computational study
Nest, M.; Remacle, Françoise ULg; Levine, R. D.

in New Journal of Physics (2008), 10

A time-dependent multiconfiguration method with a large electronic basis set is used to compute the response of all the electrons of LiH to a few-cycle intense pump field followed by a probe pulse. The ... [more ▼]

A time-dependent multiconfiguration method with a large electronic basis set is used to compute the response of all the electrons of LiH to a few-cycle intense pump field followed by a probe pulse. The ultrashort pump pulse excites a coherent superposition of stationary electronic states and, by changing the pump parameters such as intensity, duration, polarization and phase of carrier frequency, one can steer the motion of the electrons. Particular attention is given to the control provided by the polarization and by the phase. For example, a change in polarization is used to select an electronic wave packet that is rotating in a plane perpendicular to the bond or rotation in a plane containing the bond. The electronic wave packet can be probed by a delayed second pulse. This delayed probe pulse is also included in the Hamiltonian with the result that