Ionization of the hydrogen molecular ion under linearly polarized intense laser fields is simulated by direct solution of the fixed-nuclei time-dependent Schrödinger equation for λ = 790 nm and I = 1 × 1014 W cm−2. Different adaptive grids used in this study produced very similar results. The results are in agreement with, and thus support, the results of recent calculations carried out by other researchers. Detailed structure of the ionization rates is presented which has not been reported so far in the literature. The use of the virtual detector method resulted in more details of the ionization rates of the hydrogen ion molecule and hydrogen atom. This method especially allowed a simultaneous detection of the parallel and perpendicular components of the ionization rates.
Nanostructure assemblies based on ferrioxamation of gold-mercaptopropionic acid, Au-MPA-DFO-Fe(III), are prepared via in-situ and ex-situ approaches for the first time and described by cyclic voltammetry (CV), square wave voltammetry (SWV), electrochemical impedance spectroscopy (EIS) and scanning tunneling microscopy (STM) techniques. The assemblies formed via the two approaches show different structures, topologies, and electrochemical kinetics. The STM images show that the Au-MPA-DFO layer is formed in rodlike arrays with 3À4 nm peak-to-peak distances, while the arrays of the Au-MPA-DFO-Fe(III) layers formed by the in-situ and ex-situ methods, respectively with sharp and round ridges, have similar peak-to-peak distances of 2À3 nm. The CVs reveal that the Fe(III) ion immobilized by the ex-situ method is more stable by 14.48 kJ/mol. The relative amounts of the adsorbed Fe(III) ions via the in-situ and ex-situ methods, Γ ex-situ /Γ in-situ , obtained by CV and EIS are 1.33 ( 0.13 and 1.37 ( 0.19, respectively. Faradaic and impedimetric surface titrations both predict a surface-pK a of ∼9.4 for the Au-MPA-DFO self-assembled monolayer (SAM).
A new simulation box setup is introduced for the precise description of the wavepacket evolution of two electronic systems in intense laser pulses. In this box, the regions of the hydrogen molecule H(2), and singly and doubly ionized species, H(2) (+) and H(2) (+2), are well discernible and their time-dependent populations are calculated at different laser field intensities. In addition, some new regions are introduced and characterized as quasi-double ionization and their time-dependencies on the laser field intensity are calculated and analyzed. The adopted simulation box setup is special in that it assures proper evaluation of the second ionization. In this study, the dynamics of the electrons and nuclei of the hydrogen molecule are separated based on the adiabatic approximation. The time-dependent Schrödinger and Newton equations are solved simultaneously for the electrons and the nuclei, respectively. Laser pulses of 390 nm wavelength at four different intensities (i.e., 1 × 10(14), 5 × 10(14), 1 × 10(15), and 5 × 10(15) W cm(-2)) are used in these simulations. Details of the central H(2) region are also presented and discussed. This region is divided into four sub-regions related to the ionic state H(+)H(-) and covalent (natural) state HH. The effect of the motion of nuclei on the enhanced ionization is discussed. Finally, some different time-dependent properties are calculated, their dependencies on the intensity of the laser pulse are studied, and their correlations with the populations of different regions are analyzed.
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