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We investigate the interaction of molecular/atomic hydrogen with the Li surface. We calculate the potential energy surfaces (PESs) for H 2 and the potential energy curves (PECs) for H at symmetric sites on a Li(100) surface within the density functional theory. The PESs results show the dependence of the energy barriers for H 2 dissociative adsorption and the stable adsorption sites for the dissociated H atoms on the H 2 center-of-mass (CM) position and the H 2 orientation relative to the surface. Also, reaction paths for the direct absorption of H 2 can be seen when the H 2 CM is directly above the bridge site of the Li(100) surface. Meanwhile, the PECs results indicate that the energy barriers for H absorption and the stable H adsorption sites depend on the H lateral position relative to the surface. A very low energy barrier was observed for H absorption on the bridge site of the surface. Finally, we present a practical explanation of the PESs' and PECs' dependence on the H 2 position and orientation r...

We report that by controlling the orientation of the impinging O 2 before it binds to heme, we can lower the activation barrier of O 2 dissociation from the heme–O 2 adduct to a value comparable to the activation barrier of the well-known platinum catalyst, using ab initio calculations based on density functional theory (DFT). The activation barrier for the O–O bond cleavage for the side-on heme–O 2 configuration is lower than that for the end-on heme–O 2 configuration. Our results suggest that heme may be utilized as a cathode electrode catalyst in polymer electrolyte fuel cells (PEFCs).

We focus on a variant of the heme protein, i.e., the recently discovered neuroglobin (NHb) and cytoglobin (CHb), looking for clues with regard to possible applications in polymer electrolyte fuel cells (PEFCs), in a quest to design nanomaterials that would replace the expensive platinum catalysts used in PEFC electrodes. The active heme sites of these two new members of the globin superfamily display a functionally-relevant heme iron atom, whose sixth coordination site is occupied by an endogenous (internal) protein ligand, in the absence of exogenous (external) ligands, such as O2, CO, and NO. Density Functional Theory (DFT)-based calculation results indicate a possible means of controlling the adsorption and desorption on adsorbed O2 through the endogenous protein ligand occupying the sixth coordination site of the central iron atom in the heme structure. [DOI: 10.1380/ejssnt.2005.233]

We present a theoretical method to study diluted magnetic semiconductors, beyond the single-site approximation, extending the dynamical cluster approximation (DCA). By the method, we can consider the nonlocal correlations due to disorder and discuss effects of the direct exchange interaction between magnetic impurities on the properties of the itinerant carriers. We apply the method to a three-dimensional cubic lattice system with random localized spins. We show that the strong antiferromagnetic superexchange interaction between nearest-neighbor sites suppresses the polarization of the carrier spins.

We investigate and discuss how hydrogen behaves at the edges of a graphite sheet, in particular the armchair edge. Our density functional theory-based calculations results show that, in contrast to the zigzag edge [W.A. Dino, H. Nakanishi, H. Kasai, T. Sugimoto, T. Kondoe, e-J. Surf. Sci. Nanotech. 2 (2004) 77. [25] ], regardless of orientation, there is an activation barrier hindering H 2 dissociation at the armchair edges. And once they do get dissociatively adsorbed at the armchair edges, we find that it would be extremely hard to desorb the H from their adsorption sites at the armchair edges. Furthermore, we also found that, consistent with our earlier conclusions [W.A. Dino, Y. Miura, H. Nakanishi, H. Kasai, T. Sugimoto, J. Phys. Soc. Jpn. 72 (2003) 1867. [24] ], it is unlikely that we would find a whole H 2 in between plain graphite sheets.

Local magnetic moments in benzenes of a multiple-decked sandwich cluster, namely, Mnn(C6H6)n+1 (n = 1,2) are investigated using density functional theory. A significant increase in the magnetic moments of benzenes was found in the 2pz orbitals. From the values of the local magnetic moments of Mn(C6H6)2 and Mn2(C6H6)3, we find that the local magnetic moment of benzene in the centre of the chain is larger than that at the edge position. These results indicate a promising possibility of changing the magnetic properties of benzenes using a magnetic material.

We investigate the electronic and magnetic properties of a metallic (3, 3) single-walled carbon nanotube (SWCNT) filled with a linear Fe nanowire, based on the ab initio spin-polarized density functional theory. We find that in the stable structure the Fe-filled (3, 3), (5, 0) SWCNTs exhibit semiconducting properties, and the Fe nanowires lose their magnetic moment, while the (4, 4), (5, 5), (6, 6), (6, 0) SWCNTs having larger radius with linear Fe nanowires are metallic, and show magnetic moments.

We investigate the transport properties of Fe thin films on Cu(111) based on first principles calculation. We calculate the electron current through these Fe thin films, which can be observed by using a double-tipped scanning tunnelling microscope. We find that the conductance is majority spin polarized. On the basis of the band structures for this system, we discuss the origin of these interesting transport properties.

We investigate and discuss spin polarization effects on cyclohexane (C6H12) dehydrogenation using a Ni atom as a test catalyst, by performing total energy calculations based on the density functional theory (DFT). We compare the results with those of the well known catalyst Pt. We consider the process where cyclohexane approaches a transition metal M (M: Ni and Pt), and determine the reaction paths from the calculated potential energy surfaces (PESs) for singlet cyclohexane/M and triplet cyclohexane/Ni systems. Unlike the singlet cyclohexane/Ni, no energy is required to separate cyclohexyl intermediate (C6H11) from the H–Ni system for the triplet cyclohexane/Ni. Our results suggest that the catalytic reactivity of spin-polarized Ni becomes close to that of Pt, which is considered to be, up to now, the best catalyst for cyclohexane dehydrogenation.

We investigate the magnetic properties for Fe adatoms on Si(001) on the basis of first-principles calculations. For the Si(001) surface, we consider systems having buckling dimers and H-terminated symmetric dimers. We find that the magnetic moment of the Fe adatom on the latter surface is larger than that of the Fe adatom on the former surface. The results positively indicate potential applications in the realization/fabrication of nanospintronics devices.

We present a theoretical method for studying diluted magnetic semiconductors, extending the dynamical cluster approximation. The precursor effects of the localization and the direct exchange interaction between magnetic impurities can be considered in the method. We apply the method to the two-dimensional square lattice system with random localized spins. We show that the strong antiferromagnetic superexchange interaction between nearest-neighbour sites suppresses the polarization of the carrier spin.

We investigate the quantum mechanical behavior, in particular, the vibrational properties, of H atoms adsorbed on metal surfaces. We carry out density functional theory–based calculations of the relevant potential energy curves (PECs) for the hydrogen on Cu(111) and Ir(111) systems and construct the adiabatic three-dimensional potential energy surfaces (PESs) based on the obtained PECs. The wave functions and the corresponding energies for the hydrogen motion on the PESs are calculated within the framework of the variation method. The results show that the H atom is adsorbed at the threehold hollow site of Cu(111) and it is strongly localized. On the other hand, on the Ir(111), the H atom is adsorbed at the top site and it exhibits delocalized features. Furthermore, our calculated energies for vibrationally excited hydrogen and deuterium adsorbed on Cu(111) and Ir(111) agree well with the corresponding recently observed high-resolution electron energy-loss spectroscopy loss peaks.

We investigate the adhesion of poly(phenylene sulfide) (PPS) on aluminum, copper, silver and gold through simulations involving PPS monomers and single metal atoms. Density functional theory based-total energy calculation results show that PPS binds best to aluminum through the sulfur end of the monomer. Although adhesion to copper is strongest in the other two schemes examined, the energy curves suggest that these may not proceed directly. The models involving silver in general showed the least affinity for PPS adhesion.

We investigate the electronic structures of Fe, Co and Ni nanowires on Cu(1 1 1) within the density functional theory. Among these nanowires, we find that the Fe nanowires exhibit the largest magnetic moment. For the Fe nanowires, we also calculate the electron band structure and the corresponding wave functions in real space. We find some spin polarized electron states localized along Fe nanowires in real space whose energy bands exhibit one-dimensional properties. On the basis of the numerical results, we discuss the origin of these interesting properties and also the possibility of observing spin-dependent current through these Fe nanowires.

We calculate the corresponding two-dimensional (2D) potential energy surfaces (PESs) for one fixed lateral H2 center of mass position and one H2 orientation on Mg(0 0 0 1), Ti(0 0 0 1) Ni(1 1 1), Pd(1 1 1) and La(0 0 0 1) surfaces within the density functional theory. From the results, on the Ti, Ni, Pd and La surfaces, the energy barriers for H2 dissociative adsorption are either small or negligible. On the other hand, on the Mg surface, a high energy barrier exists. Furthermore, we can practically explain these differences among the surfaces by considering the differences in the valence electron configurations of the substrate atoms.

We investigate the spin polarization of a multiple-decked sandwich cluster, viz ., M n (C 6 H 6 ) n +1 . As a first step, we consider M n (C 6 H 6 ) n +1 clusters with n =1 and M = Mn, Fe, Co. Based on the density functional theory, we find an increase in the magnetic moment of the benzene clusters, and a decrease in the magnetic moment of M in the M(C 6 H 6 ) 2 systems. From increased magnetic moment of benzenes, we find a way to inject spin to benzenes through 2 p z orbitals.

Dissociative adsorption of hyperthermal O 2 molecules on Cu{1 0 0} was investigated by X-ray photoemission spectroscopy in conjunction with a synchrotron light source. From precise measurements of the O-uptake curves, it was found that the dissociative adsorption of hyperthermal O 2 molecules follows a simple Langmuir-type model and the reaction order depends on the incident energy. An O 2 δ − -mediated adsorption mechanism can interpret the incident-energy dependence of the reaction order. These results suggest the possibility of tuning dissociative adsorption via the selection of the incident kinetic energy of the impinging O 2 molecules.

To investigate cyclohexane dehydrogenation by a transition metal M (M: Pt, Pd, Ni and Cu) atom, we perform total energy calculations, based on the density functional theory. We consider the process where cyclohexane approaches the M atom. Upon interacting with the M atom, the M atom draws an H atom from the cyclohexane, forming an H–M bond. With a broken C–H bond, the dehydrogenated cyclohexane separates from the M atom. Of the M elements we investigated, a Pt atom exhibited the highest reactivity. In breaking the C–H bond of the cyclohexane, the σ donation dominates for a Pd and Cu atom as compared with the Pt atom, and the π back-donation dominates for a Ni atom as compared with the Pt atom. The results indicate that the excess charge transfer requires more energy for breaking the C–H bond of the cyclohexane with the Pd, Ni and Cu atom.

We performed quantum dynamics calculations using previously obtained potential energy surfaces (PESs) for the dissociative adsorption of hydrogen molecule incident on a Mg(0001), Ti(0001), and La(0001) surface. Based on the sticking probability plots we obtained as functions of the incidence H 2 beam energy, La is the best material for hydrogen storage, followed by Ti, and then by Mg. This is due to the absence of an activation barrier in the H 2 /La(0001) system. Both H 2 /Ti(0001) and H 2 /Mg(0001) systems have activation barriers, but the H 2 /Ti(0001) system has a very small activation barrier far from the curved region of the reaction path, while the H 2 /Mg(0001) system has a high activation barrier close to the curved region along the reaction path. Our results also indicate that the sticking probability has some dependence on the vibrational state of the impending H 2 molecule for the Mg, Ti and La surfaces. The degree of dependence still varies in each metal. Vibrational effect is most observed w...

We investigate and discuss spin polarization effects on cyclohexane (C6H12) dehydrogenation with a Ni atom, by performing total energy calculations based on the density functional theory (DFT). We consider the process where cyclohexane approaches the Ni atom, and determine the reaction paths from the calculated potential energy surfaces (PESs) for singlet and triplet systems. The C-H bond dissociation processes of the cyclohexane for both singlet and triplet systems are almost the same. After interacting with the Ni atom, the Ni atom draws an H atom from the cyclohexane, and an H-Ni bond is formed. With the C-H bond broken, cyclohexyl intermediate (C6H11) separates from the Ni atom. For the triplet system, however, no energy is required to separate the cyclohexyl from the H-Ni system due to the repulsion between up-spin electrons, resulting from the up-spin electron transfer from the Ni atom to the C atom. Therefore, it indicates that the magnetic properties of the Ni atom are favorable for the cyclohexane dehydrogenation. [DOI: 10.1380/ejssnt.2004.200]

We consider hemoglobin (Hb) components for possible use as cathode electrode catalyst in polymer electrolyte fuel cells (PEFCs). We choose iron-porphyrin (FeP) and (imidazole)FeP [(Im)FeP] as a representative heme complex of the Hb active site, and investigate their catalytic activities for O2 dissociation using it ab initio calculations based on density functional theory (DFT). The imidazole ligand suppresses the donation/back-donation of electrons between Fe and O2, resulting in the weakening of the Fe-O2 bond and the strengthening of the O-O bond. Therefore, the catalytic activity of FeP is higher than that of (Im)FeP. [DOI: 10.1380/ejssnt.2004.226]

We theoretically investigate the effects of nonmagnetic impurities on the properties of high-Tc cuprate superconductors, on the basis of the d-p model, within the fluctuation-exchange approximation and the coherent potential approximation. The obtained reduction of Tc is consistent with the experimental values. We find a large reduction in the Tc at the low doping concentrations corresponding to the optimum regime.

Here we consider a nanoscale material consisting of two Fe atoms sitting on a planar C 10 cluster. On the basis of the density functional theory (DFT), we demonstrate how it is feasible to induce s...

Based on the density functional theory, we investigate and discuss what possible stable configurations hydrogen might assume, once found inside/between graphite layers stacked in an A B configurati...

As a representative Kondo system, consisting of a magnetic atom adsorbed on a metal surface, we consider a Co adatom on a Cu(111) surface. We introduce general expressions for the tunneling current and the differential conductance dI/dV, and discuss the corresponding spatial and temperature dependencies of the dI/dV line shapes that can be observed when the system is probed with a scanning tunneling microscope (STM). Starting with the STM tip sufficiently far from the Co adatom, the corresponding dI/dV line shape initially has an asymmetric structure about the Fermi level, which gradually becomes symmetric with decreasing STM tip–Co adatom distance, due to the competition between first-order (direct electron tunneling from the STM tip to the metal surface) and second-order (via the magnetic adsorbate) tunneling processes. The corresponding line shape also shows a strong temperature dependence, increasing in width with increasing temperature. As an aid to studying and observing these temperature dependenci...

We investigate the effects of photoexcited-hole decay on time-resolved two-photon photoemission spectra of metal surfaces by non-equilibrium Green function method. We show that it is necessary for calculating the photoelectron intensity to introduce a Green function depending on the observation time of the photoelectron. The photoexcited-hole decay causes the loss of coherence of the system and hence accounts for acceleration of the decay of the photoexcited-electron density. Then the effective lifetimes estimated from the photoelectron intensity as a function of the pump–probe delay time can be the lifetimes of the photoexcited ‘(non-excitonic) electron–hole pairs’ even when direct interactions between photoexcited electrons and holes are negligible while it is usually considered that the effective lifetimes correspond to the electron lifetimes.

One of the ultimate goals of surface science is to be able to design and control reactions as they progress on surfaces. This entails an atomic-level understanding of the fundamental principles (elementary processes) underlying the bond-making and bond-breaking at surfaces. Our current understanding has gained significantly from systematic experimental and theoretical studies on such benchmark systems as the interaction of hydrogen with metal surfaces. Yet, fundamental, examples of surface science-based reaction design are extremely few. Here, we consider the ortho – para ( o – p ) H 2 conversion as a case study. We invoke two processes derived from fundamental, surface science insights, based on the effect of molecular orientation on the hydrogen-solid surface reaction, viz., dynamical quantum filtering (DQF) and Steering , and apply them to enhance the o – p H 2 conversion yield/rate. The orientation dependence of the o – p H 2 conversion ( steric effect , SE) dictates that cartwheel-like rotating (CLR) H 2 will have a higher rate of conversion than helicopter-like rotating (HLR) H 2 . Applying DQF, we can then prepare rotationally aligned H 2 , doing either HLR or CLR. This enables us to increase the o – p H 2 conversion yield.

We investigate and discuss the effects of the kinetic energy ( E t ) of the incident hydrogen atom on the hydrogen abstraction dynamics on Cu(1 1 0) by performing quantum dynamics calculations on an ab initio potential energy surface. Our calculation results show that the hydrogen abstraction probabilities on Cu(1 1 0) initially increase, then decrease, with increasing E t , in the energy range E t =0.05–1.0 [eV]. Furthermore, we show that the mean vibrational energy of the product hydrogen molecules increases with increasing E t , while the mean surface parallel translational energy of the product hydrogen molecules decreases with increasing E t . From these results, we can conclude that increasing E t mainly enhances the excitation of the vibrational motion, rather than the surface parallel motion of product hydrogen molecules.

We have investigated the transport and magnetic properties of the atom bridge made from magnetic materials, which is the atom-scale wire constructed between a scanning tunneling microscope (STM) tip and a solid surface, by the use of ab initio calculations. In the case of the twisted ladder structure atom bridge made of Fe, we have found that the magnetic state of the bridge changes from ferromagnetic to paramagnetic, as we compress the bridge in length. We report the spin dependent quantized conductance of the bridge. And we discuss the origin of a change in transport properties as we compress the bridge in length.

We investigate and discuss the interaction of H2 with graphene based on density functional (DFT) theory. We calculate the potential energy surfaces for the dissociative adsorption of H2 on highly symmetric sites on graphene. Our calculation results show that reconstructions of the carbon atoms play an important role in the H2 -graphene interactions. Activation barrier for H2 dissociation on an unrelaxed graphene is considerably high, ∼4.3 eV for a T–H–T geometry and ∼4.7 eV for a T–B–T geometry. The T–H–T(T–B–T) geometry means that the center of mass position of H2 is at the hollow(bridge) site, and the two H atoms are directed towards the top sites on the graphene. On the other hand, when the carbon atoms are allowed to relax, the activation barrier decreases, and becoming 3.3 eV for the T–H–T geometry and 3.9 eV for the T–B–T geometry. In this case, the two carbon atoms near the hydrogen atoms move 0.33 A towards the gas phase for the T–H–T geometry and 0.26 A for the T–B–T geometry.

Hydrogen absorption into the Pd (111) surface and desorption from the subsurface to the Pd (111) surface are investigated. In particular, the role of hydrogen-induced relaxation of the Pd lattice in absorption and desorption processes are studied. We performed the quantum dynamics calculations of H/Pd (111) absorption and desorption probabilities that include the surface atoms' motion using the time-independent coupled-channel method. Based on the calculation results for both the hydrogen absorption and desorption probabilities, we find that the hydrogen motion and the surface lattice relaxation are dynamically coupled. Depending on the hydrogen translational energy, the surface lattice motion either promotes or hinders the penetration of hydrogen into (desorption from) the surface (subsurface). Furthermore, the surface temperature dependence of hydrogen desorption dynamics is investigated. Based on the calculation results, we find that the hydrogen desorption is promoted by an increase in the surface temperature.

Microscopic mechanisms of energy relaxation and dephasing in two-photon photoemission (2PPE) from metal surfaces are investigated by nonequilibrium Green function method. It is shown that the dephasing time corresponds to the lifetime of a hole excited in an occupied state by a pump photon. The hole lifetime also affects the energy relaxation time which is usually considered to be the intrinsic electron lifetime of an unoccupied state. The density matrix method can reproduce the results by the Green function method well, however, fails to estimate the effects of the hole scattering properly. Based on the obtained results, a new physical interpretation of the energy relaxation time and the dephasing time of metals is proposed.

We consider cluster model of FeNi4 cluster (as material target) where Fe ion is surrounded by four Ni ions in order to understand the mechanisms involved in the reactive ion etching (RIE) processes on magnetic surfaces(e.g., FeNi surface). By considering CO ions as reactive gases, we etch Fe ion from the cluster surface providing ion pentacarbonyl, i.e., Fe(CO)5. By density functional theory based first principle calculations, we calculate the potential energy surface(PES) of the system and describe the mechanism of the reaction. Based on the two chosen pathways for initial and final states, we show that the RIE processes follow the pathway that gives us minimum energy.

We study effects of an oxygen vacancy on the electronic state of the CuO 2 plane in the normal state, on the basis of the d – p model. We calculate the local density of states at copper sites and oxygen sites around the p x -oxygen vacancy, at T = T c . The spatial distribution has a shape which oscillates along the diagonal directions, reflecting the form of the Fermi surface. We find that another gentle oscillation along the X axis appears in the local density of states of d - and p x -electron, while disappears in that of p y -electron due to the crystal structure.

We investigate how the deformation of an atom bridge, made of Fe, between a scanning tunneling microscope tip and a solid surface affects the magnetic state of the atom bridge within the density functional simulations. For atom bridges of chain structure and ladder structure, we calculate their total energies and their magnetic moments as we elongate and/or compress the bridge in length. On the basis of the numerical results, we show that the Fe atom bridge of a twisted ladder structure is stable to induce the change in the magnetic state as the bridge is compressed in length.

We study the ground state energy/properties of a system of interacting electrons confined one-dimensionally, with the aid of the Bethe ansatz method. We first derive a set of fundamental equations, explicitly taking into account the confinement of the system. We then obtain the numerical solution of this set of fundamental equations to determine the ground state energy/properties for a few electrons in the system. On the basis of the obtained results, we discuss the effects of the confinement and the electron–electron interaction on the ground state properties of the system of interacting electrons confined in one-dimension, comparing the results with those for a system of interacting electrons with periodic boundaries.

Steric effect on the o-p conversion of a H 2 interacting with a 3d impurity sitting on a metal oxide surface is investigated by comparing the o-p conversion yield/rate for a H 2 doing cartwheel-like rotation (i.e., the rotational axis of H 2 is parallel to the surface) with that for a H 2 doing helicopter-like rotation (i.e., the rotational axis of H 2 is perpendicular to the surface). The yield of o-p H 2 conversion is calculated by using the perturbation theory, where Fermi's contact interaction (intra-molecular hyperfine contact interaction) and the H 2 -surface electron exchange interaction (Coulomb interaction) represent the perturbation terms. On the basis of the calculated results, for the transition from the lowest rotational state of an ortho H 2 (with rotational quantum number j = 1) to the lowest rotational state of a para H 2 (j = 0), the o-p H 2 conversion yield shows that for a H 2 doing cartwheel-like rotation is higher than that for a H 2 doing helicopter-like rotation.

We study the effects of nonmagnetic impurities on the electronic states of CuO 2 planes in copper oxides. We calculate the local density of states at the copper sites and the oxygen sites, around the impurities. The local density of states in the CuO 2 plane with the impurities increases or decreases, depending on the energy ω , as compared with those without the impurities. The spatial distribution of the local density of states has an anisotropic shape in the vicinity of the Fermi energy ω ∼ ω F . At ϵ p (p-level) ω ϵ d (d-level), there is a difference in the spatial distribution of the local density of states between the d- and p-electrons, while at other energies, those of the d- and p-electrons are practically the same.

We investigate the magnetic properties of atom bridges, made of Fe and Ni, between a scanning tunneling microscope tip and a solid surface, within the density functional theory. We consider an Fe 1− α Ni α atom bridge with a twisted ladder structure. Relative to a pure Fe bridge which is in a high-spin ferromagnetic state, we calculate the magnetic moment of the bridge as α increases. On the basis of the calculation results, we show that the Fe and Ni atoms in the bridge also stay in high-spin ferromagnetic states (the magnetic moment per atom is ∼3 μ B for Fe and ∼0.9 μ B for Ni) as α increases, and the mean magnetic moment per atom decreases linearly with increasing α .

Employing the Newns–Anderson model to describe a Co adatom placed at one focus of an elliptical quantum corral on a Cu(1 1 1) surface, we theoretically investigate the mechanism behind how so-called quantum mirages could be observed at the opposite empty focus. First, we try reproducing the experimental results of the differential conductance dI/dV spectra measured at the empty focus, which exhibit features very similar to those measured at the Co-occupied focus. Furthermore, we consider the temperature dependence of the dI/dV spectra at the two foci. Finally, we consider the structure of the dI/dV spectra when the STM tip is placed very close to the Co adatom (at the Co-occupied focus) and a metal surface (at the empty focus).

We investigate and discuss the effects of dynamical quantum filtering on the scattering dynamics of H2 on Cu(001); we perform coupled-channel calculations, including all six degrees of freedom of H2, on an ab initio potential energy surface. Our results show that cartwheel-like rotating H2 molecules (with their angular momentum vectors j predominantly oriented parallel to the surface) exhibit strong specular scattering on Cu(001), while helicopter-like rotating H2 molecules (with their angular momentum vectors j predominantly oriented perpendicular to the surface) exhibit off-specular scattering on Cu(001). These results indicate that we can obtain H2 molecules with aligned angular momentum vectors j, by scattering them from solid surfaces.

Vibrational properties of an H atom adsorbed on Pt(1 1 1) are studied theoretically. The potential energy curves (PECs) for the H atom motion on Pt(1 1 1) are calculated within the density functional theory, and the adiabatic three-dimensional potential energy surfaces (PESs) are constructed based on the obtained PECs. The wave functions and their energies for the H atom motion on the PESs are calculated within the framework of the variation method. The results show that even in the low excited vibrational-states of the H atom adsorbed on Pt(1 1 1), the behavior of the atom does not fully correspond to the harmonic oscillator states perpendicular nor parallel to the surface, and show the complicated vibration, around the well-defined adsorption sites.

The scattering dynamics of D2 from NiAl(1 1 0) has been investigated both experimentally and theoretically. Diffraction and rotational transitions of D2 from NiAl(1 1 0)[1 1 0] have been measured at incident energies between 88 and 157 meV. The measurements were done using a setup which allows recording of diffraction patterns at a fixed angle of incidence. Elastic first-order diffraction and rotationally inelastic diffraction (RID) peaks were resolved over the whole incident energy range studied. The 0→2 transition probability was found to be about a factor of 2 higher than the one reported on Cu(0 0 1), whereas the 2→0 transition remained constant in the energy range investigated. Concerning the two rotational transition probabilities observed in experiment, one major conclusion of our work is that the behaviour they exhibit as a function of incident energy is independent of angle of incidence. All these observations are well reproduced by ab initio quantum mechanical calculations.

We study the dynamics of H abstraction from Cu(1 1 1) by performing quantum dynamics calculations. We introduce a new theoretical approach that considers both quantum mechanically direct (the impinging H directly abstracts an adsorbed H) and indirect (the impinging H diffuses on the surface before it abstracts an adsorbed H) processes for H abstraction, and investigate how the coverage of adsorbed H on Cu(1 1 1) affects the vibrational and surface-parallel translational energy distribution of product H2. We expect that the H abstraction dynamics would depend on the coverage, because the shape of the corrugation depends on the coverage. Our results, calculated for the case when the kinetic energy of the incident H Et=0.1 (eV), confirm this expectation. The normalised mean vibrational energies of product H2 decrease with decreasing coverage. On the other hand, the normalised mean surface-parallel translation energies of product H2 increase with decreasing coverage. These results indicate that for the low coverage case, H abstraction occurs mainly through the indirect process, where the vibrational excitation of product H2 is suppressed, and the excitation for the surface-parallel translational motion of product H2 is enhanced, as compared with those for the high coverage case, where the H abstraction can occur through both direct and indirect processes.

Ultrafast electron dynamics in image states of metals are investigated by Green function method involving off-diagonal elements of self-energy functions, which represent virtual electron transitions between different image states. The diagonal and off-diagonal elements of Green functions, which represent the electron densities of the image states with quantum numbers from 3 to 6 and the probability amplitude of electron propagation between different image states, respectively, are calculated by treating the self-energy functions within the GW approximation. The virtual electron transitions between different image states account for occurrence of quantum beats and acceleration and deceleration of the decay of electron densities, as compared with the intrinsic decay rates determined by the imaginary parts of the diagonal elements of the self-energy functions. It is quantitatively demonstrated that the effects of the virtual transitions are marked especially for image states with large quantum numbers.

We investigate and discuss isotope effects on hydrogen abstraction from Cu(111) by performing quantum dynamics calculations that consider both direct (an impinging hydrogen atom directly abstracts an adsorbed hydrogen atom) and indirect (the impinging hydrogen atom diffuses across the surface before it abstracts an adsorbed hydrogen atom) processes quantum mechanically. Our calculation results show that the abstraction reaction probabilities Preac are 0.742(D-on-D) > 0.640(H-on-D) > 0.594(H-on-H) > 0.533(D-on-H). (Note that the term `X-on-Y' indicates abstraction of Y atoms adsorbed on the surface by gas-phase X atoms.) Furthermore, the mean normal translational and vibrational energies for H-on-D are larger than those for D-on-H, while the mean parallel translational energy for D-on-H is comparable with that for H-on-D. This implies that the decrease in the abstraction reaction probability for D-on-H, as compared with that for H-on-D, is mainly due to the decrease in the frequency of occurrence of the direct process in abstraction reactions.