Search results for "binding energy"
showing 10 items of 248 documents
Counter anion binding in the phenoxyimine, salan and metallocene olefin polymerization catalysts activated with perfluorophenylborate
2012
Abstract Ion pair separation is a process that may influence the activity of homogeneous catalysts of olefin polymerization. We have studied the energy of separation for selected titanium and zirconium metallocene and post-metallocene catalytic ion pairs by means of DFT, dispersion-corrected DFT and Paired Interacting Orbitals method (PIO). Unusually weak cation–anion interactions in the bis(phenoxyimine) systems were attributed to strong electron-donating properties of the phenoxyimine ligands. Energy decomposition analysis (EDA) revealed that almost 70% of the counter ion binding energy results from electrostatic interactions. The PIO method made it possible to analyze the nature of the c…
The dissociation channels of silver clusters Agn+, 3 ≤ n ≤ 20
1996
Abstract The low energy dissociation channels of silver cluster ions Agn+, 3 ≤ n ≤ 20 are determined by collision-induced dissociation (CID) in a Penning trap. While for most cluster sizes the first fragment cluster ion is produced by monomer evaporation, the fragment ion of small odd-sized clusters has two atoms less than their precursors indicating an evaporation of dimers. The results are compared to similar CID studies on gold cluster ions, photofragmentation patterns, abundance spectra for various silver-cluster production techniques and calculated binding energies.
Fragmentation pattern of gold clusters collided with xenon atoms
1994
Abstract The dissociation channels of gold cluster ions Au n + (2 ≤ n ≤ 23) have been investigated via collision induced dissociation in a Penning trap. Excited odd cluster ions with n ≤ 15 decay by evaporation of dimers, all others decay by monomer evaporation. Information on the binding energies is deduced from these dissociation channels.
Regularized pseudopotential for mean-field calculations
2019
We present preliminary results obtained with a finite-range two-body pseudopotential complemented with zero-range spin-orbit and density-dependent terms. After discussing the penalty function used to adjust parameters, we discuss predictions for binding energies of spherical nuclei calculated at the mean-field level, and we compare them with those obtained using the standard Gogny D1S finite-range effective interaction.
XPS study of leached glass surfaces
1990
Abstract By use of a special deconvolution algorithm, it was possible to decompose the XPS O 1s signal into several components reflecting different oxygen bonds. The influence of exposure in vacuo, environmental atmosphere, distilled water, and in a polish solution as corrosive media on the surface of different glasses has been studied. The O 1s signals of fused silica, Na 2 O· n SiO 2 glasses, a BaO·SiO 2 and a BaOB 2 O 3 SiO 2 glass (Schott SK 16) were analyzed. On the glass surfaces, leached layers were formed and analyzed qualitatively and semiquantitatively by XPS and optical and infrared methods. As a reference, virgin surfaces of samples broken in ultrahigh vacuum have been used. T…
High-precision Penning-trap mass measurements of heavy xenon isotopes for nuclear structure studies
2009
With the double Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN the masses of the neutron-rich isotopes $^{136\ensuremath{-}146}\mathrm{Xe}$ were measured with a relative uncertainty of the order of ${10}^{\ensuremath{-}8}$ to ${10}^{\ensuremath{-}7}$. In particular, the masses of $^{144\ensuremath{-}146}\mathrm{Xe}$ were measured for the first time. These new mass values allow one to extend calculations of the mass surface in this region. Proton-Neutron interaction strength, obtained from double differences of binding energies, relate to subtle structural effects, such as the onset of octupole correlations, the growth of collectivity, and its relation to the underlying shell model l…
Probing the chemical interaction between iridium nanoparticles and ionic liquid by XPS analysis
2009
Abstract In situ X-ray photoelectron spectroscopy analysis of Ir(0) nanoparticles (1.6 ± 0.3 nm) dispersed in imidazolium ionic liquid (EMI.EtSO4) shows evidences of the effective interaction between the metallic clusters and the surrounding liquid. By monitoring the C 1s signal of the ionic liquid one observes a change of the binding energy in one of its components (C2) when in the presence of Ir nanoparticles. This result was corroborated by isotope labeling experiments.
Weak interactions between trivalent pnictogen centers: computational analysis of bonding in dimers X3E...EX3 (E = pnictogen, X = halogen).
2009
The nature of weak interactions in dimers X(3)E...EX(3) (E = N-Bi, X = F-I) was investigated by wave function and density functional theory (DFT)-based methods. Out of the 20 systems studied, 10 are found to be bound at the CP-MP2 and LMP2 levels of theory. Detailed partition of the interaction energy into different components revealed that dispersion is the primary force holding the dimers together but there also exists an important ionic component whose contribution increases with increasing halogen size. As expected, standard density functionals fail to describe bonding in the studied systems. However, the performance of DFT methods can be easily improved via empirical dispersion correct…
Two-step impact of Amphotericin B (AmB) on lipid membranes: ESR experiment and computer simulations.
2013
In this study, the electron spin resonance (ESR) method was used to examine the effect of Amphotericin B (AmB) molecules on the fluidity of model membranes made of dipalmitoylphosphatidylcholine (DPPC). The changes occurring under increased AmB concentrations in the spectroscopic parameters of spin probes placed in liposomes were determined. Three probes were used, penetrating the membrane at different depths which allowed the changes in its fluidity to be found in the transverse section. A computer model of the surface layer of membrane, with AmB admixture, was developed and subjected to computer simulation. The effect of changing concentration of the admixture on the binding energy in the…
Complex, energy-independent, local potential reproducing an absorptive phase shift and a bound state
1994
The triton binding energy, and the partly real and partly complex neutron-deuteron doublet channel elastic scattering phase shifts, calculated by means of the exact three-body theory, are used as input in the fixed-[ital l] inverse scattering theory of Marchenko. The local potentials obtained hereby are independent of energy, and complex. Their strong imaginary part reflects the strong absorption in the doublet channel arising from the opening of the deuteron breakup channel. For total orbital angular momentum [ital l] different from zero the potentials are unique, reproducing the input phase shift in the whole energy region. For [ital l]=0 where there exists, in addition, a bound state we …