Low-Energy CO Scattering at the Gas–Liquid Interface: Experimental/Theoretical Evidence for a Novel Subthermal Impulsive Scattering (STIS) Channel

In this paper we propose a new technique for drop deposition on low energy surfaces, which addresses the limitations of the classical drop deposition technique. In this classical technique, a drop is deposited on a surface by bringing a needle, holding the drop, in proximity to the solid surface. Therefore, irrespective of whether the solid surface is in air or under a liquid, it becomes extremely difficult to deposit the drop on low energy surfaces owing to the large differences between the drop-needle and the drop-substrate adhesion forces (or surface energies). In our discussed method, we overcome this difficulty for low energy surfaces immersed in a liquid. For surfaces under liquid, there is an interface in addition to the solid-liquid interface: this interface is the air-liquid interface, where the liquid gets exhausted. In our technique, we cater the (un)favorable drop spreading dynamics at this interface to ensure that the drop gets deposited on the under-liquid surface.

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CONTROL OF SUCCESSIVELY SWITCHING FROM LLCT TO ILCT AND MLCT EXCITED STATES IN PLATINUM(II) TERPYRIDYL ACETYLIDE COMPLEXES BY SEQUENTIAL PROTONATIONS

Journal of Theoretical and Computational Chemistry ◽

10.1142/s0219633608003630 ◽

2008 ◽

Vol 07 (01) ◽

pp. 103-111 ◽

Cited By ~ 2

Author(s):

SHASHA LIU ◽

YONG DING ◽

XIANGSI WANG ◽

MAODU CHEN ◽

ZHENJUN FAN

Keyword(s):

Charge Transfer ◽

Molecular Orbital ◽

Excited States ◽

Physical Mechanism ◽

Energy Levels ◽

Low Energy ◽

Orbital Energy ◽

Amino Group ◽

Ligand Charge Transfer ◽

Theoretical Evidence

Visualized theoretical evidence for successively switching from ligand-to-ligand charge transfer (LLCT) to intraligand charge transfer (ILCT) and then to metal-to-ligand charge transfer (MLCT) excited states in platinum(II) terpyridyl acetylide (PTA) complexes in low-energy absorption by sequential protonations has been given with charge transfer density, based on recently experimental report (Han X. et al., Chem Eur J13:1231, 2007). The sequential protonations have shown significant influence on the molecular geometries, ionization potential, affinity potential, and band gap of PTA. The protonations on the amino group of the ligands result in the shift of the molecular orbital energy levels of PTA. The physical mechanism of switching from LLCT to ILCT and then to MLCT excited states by sequential protonations is interpreted with the theory of molecular orbital transitions.

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Theoretical Evidence for a Stable form of Cyclic Ozone, and its Chemical Consequences

Canadian Journal of Chemistry ◽

10.1139/v73-020 ◽

1973 ◽

Vol 51 (1) ◽

pp. 139-146 ◽

Cited By ~ 52

Author(s):

James S. Wright

Keyword(s):

Configuration Interaction ◽

Pulse Radiolysis ◽

Molecular Orbital Calculation ◽

Low Energy ◽

Basis Set ◽

Slater Type Orbitals ◽

Stable Form ◽

Cyclic Form ◽

Theoretical Evidence ◽

Single Configuration

The total energy of the symmetrical, bent O3 molecule is studied as a function of internuclear angle and internuclear distance. The method used is an ab initio molecular orbital calculation with a minimum basis set of Slater-type orbitals, plus limited configuration interaction. Best single configuration energies show the existence of two stable minima: a cyclic (60°) structure and a bent (115°) structure. The cyclic structure is preferred by 48 kcal/mol, contrary to experiment (116° 48′) Configuration interaction results with two low lying orbitals show the cyclic form still preferred by 6 kcal/mol. A transition state for the bent-cyclic pathway lies 26 kcal/mol (or less) above the bent form. Based on these results, a possible low energy path via the cyclic form is proposed for the thermal decomposition of ozone. It is also proposed that cyclic ozone may have been observed in the pulse radiolysis of oxygen.

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Dissociated Σ=27 boundaries in silicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105187 ◽

1988 ◽

Vol 46 ◽

pp. 624-625

Author(s):

A. Garg ◽

W.A.T. Clark ◽

J.P. Hirth

Keyword(s):

Electron Diffraction ◽

Local Minimum ◽

Boundary Energy ◽

Coincidence Site Lattice ◽

Boundary Plane ◽

Low Energy ◽

Theoretical Understanding ◽

Site Lattice ◽

Kikuchi Pattern ◽

Analysis Techniques

In the last twenty years, a significant amount of work has been done in the theoretical understanding of grain boundaries. The various proposed grain boundary models suggest the existence of coincidence site lattice (CSL) boundaries at specific misorientations where a periodic structure representing a local minimum of energy exists between the two crystals. In general, the boundary energy depends not only upon the density of CSL sites but also upon the boundary plane, so that different facets of the same boundary have different energy. Here we describe TEM observations of the dissociation of a Σ=27 boundary in silicon in order to reduce its surface energy and attain a low energy configuration.The boundary was identified as near CSL Σ=27 {255} having a misorientation of (38.7±0.2)°/[011] by standard Kikuchi pattern, electron diffraction and trace analysis techniques. Although the boundary appeared planar, in the TEM it was found to be dissociated in some regions into a Σ=3 {111} and a Σ=9 {122} boundary, as shown in Fig. 1.

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Transfer optics for high spatial resolution electron spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105394 ◽

1988 ◽

Vol 46 ◽

pp. 666-667

Author(s):

G. G. Hembree ◽

Luo Chuan Hong ◽

P.A. Bennett ◽

J.A. Venables

Keyword(s):

Magnetic Field ◽

Scanning Transmission Electron Microscope ◽

Low Energy ◽

Objective Lens ◽

State University ◽

Arizona State University ◽

Initial Field ◽

Resolution Electron ◽

Scanning Transmission ◽

Low Energy Electrons

A new field emission scanning transmission electron microscope has been constructed for the NSF HREM facility at Arizona State University. The microscope is to be used for studies of surfaces, and incorporates several surface-related features, including provision for analysis of secondary and Auger electrons; these electrons are collected through the objective lens from either side of the sample, using the parallelizing action of the magnetic field. This collimates all the low energy electrons, which spiral in the high magnetic field. Given an initial field Bi∼1T, and a final (parallelizing) field Bf∼0.01T, all electrons emerge into a cone of semi-angle θf≤6°. The main practical problem in the way of using this well collimated beam of low energy (0-2keV) electrons is that it is travelling along the path of the (100keV) probing electron beam. To collect and analyze them, they must be deflected off the beam path with minimal effect on the probe position.

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Performance Evaluation of a Novel Type of Low-Energy Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100180525 ◽

1990 ◽

Vol 48 (1) ◽

pp. 354-355

Author(s):

Bertholdand Senftinger ◽

Helmut Liebl

Keyword(s):

Electron Microscope ◽

High Resolution ◽

Field Strength ◽

Numerical Aperture ◽

Low Energy ◽

Energy Electron ◽

High Resolution Imaging ◽

Lens System ◽

Resolution Imaging ◽

Low Energy Electron

During the last few years the investigation of clean and adsorbate-covered solid surfaces as well as thin-film growth and molecular dynamics have given rise to a constant demand for high-resolution imaging microscopy with reflected and diffracted low energy electrons as well as photo-electrons. A recent successful implementation of a UHV low-energy electron microscope by Bauer and Telieps encouraged us to construct such a low energy electron microscope (LEEM) for high-resolution imaging incorporating several novel design features, which is described more detailed elsewhere.The constraint of high field strength at the surface required to keep the aberrations caused by the accelerating field small and high UV photon intensity to get an improved signal-to-noise ratio for photoemission led to the design of a tetrode emission lens system capable of also focusing the UV light at the surface through an integrated Schwarzschild-type objective. Fig. 1 shows an axial section of the emission lens in the LEEM with sample (28) and part of the sample holder (29). The integrated mirror objective (50a, 50b) is used for visual in situ microscopic observation of the sample as well as for UV illumination. The electron optical components and the sample with accelerating field followed by an einzel lens form a tetrode system. In order to keep the field strength high, the sample is separated from the first element of the einzel lens by only 1.6 mm. With a numerical aperture of 0.5 for the Schwarzschild objective the orifice in the first element of the einzel lens has to be about 3.0 mm in diameter. Considering the much smaller distance to the sample one can expect intense distortions of the accelerating field in front of the sample. Because the achievable lateral resolution depends mainly on the quality of the first imaging step, careful investigation of the aberrations caused by the emission lens system had to be done in order to avoid sacrificing high lateral resolution for larger numerical aperture.

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