Search results for "Interaction model"
showing 10 items of 22 documents
Comparative theoretical study of the Ag–MgO (100) and (110) interfaces
1999
We have calculated the atomic and electronic structures of Ag–MgO(100) and (110) interfaces using a periodic (slab) model and an ab initio Hartree–Fock approach with a posteriori electron correlation corrections. The electronic structure information includes interatomic bond populations, effective charges, and multipole moments of ions. This information is analyzed in conjunction with the interface binding energy and the equilibrium distances for both interfaces for various coverages. There are significant differences between partly covered surfaces and surfaces with several layers of metal, and these can be understood in terms of electrostatics and the electron density changes. For complet…
Carbonyl compounds of Tc, Re, and Bh: Electronic structure, bonding, and volatility.
2018
Calculations of molecular properties of M(CO)5 and MH(CO)5, where M = Tc, Re, and Bh, and of the products of their decomposition, M(CO)4 and MH(CO)4, were performed using density functional theory and coupled-cluster methods implemented in the relativistic program suits such as ADF, DIRAC, and ReSpect. The calculated first M—CO bond dissociation energies (FBDEs) of Bh(CO)5 and BhH(CO)5 turned out to be significantly weaker than those of the corresponding Re homologs. The reason for that is the relativistic destabilization and expansion of the 6d AOs, responsible for weaker σ-forth and π-back donations in the Bh compounds. The relativistic FBDEs of M(CO)5 have, therefore, a Λ-shape behavior …
Cycloaddition of Strained Cyclic Alkenes and Ortho-Quinones : A Distortion/Interaction Analysis
2020
The chemistry of strained unsaturated cyclic compounds has experienced remarkable growth in recent years via the development of metal–free click reactions. Among these reactions, the cycloaddition of cyclopropenes and their analogues to ortho-quinones has been established as a highly promising click reaction. The present work investigates the mechanism involved in the cycloaddition of strained dienes to ortho-quinones and structural factors that would influence this reaction. For this purpose, we use B97D density functional theory calculations throughout, and for relevant cases, we use spin component–scaled MP2 calculations and single–point domain-based local pair natural orbital coupled cl…
A port-Hamiltonian Fluid-Structure Interaction Model for the Vocal folds ⁎ ⁎This work was supported by CONICYT-PFCHA/2017-21170472, and AC3E CONICYT-…
2018
Abstract Fluid-structure interaction models are of special interest for studying the energy transfer between the moving fluid and the mechanical structure in contact. The vocal folds are an example of a fluid-structure system, where the mechanical structure is usually modeled as a mass-spring-damper system. In particular, the estimation of the collision forces of the vocal folds is of high interest in the diagnosis of phonotraumatic voice pathologies. In this context, the port-Hamiltonian modeling framework focuses on the energy flux in the model and the interacting forces. In this paper, we develop a port-Hamiltonian fluid-structure interaction model based on the interconnection methodolog…
Muons in air showers at the Pierre Auger Observatory: Measurement of atmospheric production depth
2014
The surface detector array of the Pierre Auger Observatory provides information about the longitudinal development of the muonic component of extensive air showers. Using the timing information from the flash analog-to-digital converter traces of surface detectors far from the shower core, it is possible to reconstruct a muon production depth distribution. We characterize the goodness of this reconstruction for zenith angles around 60° and different energies of the primary particle. From these distributions, we define Xμmax as the depth along the shower axis where the production of muons reaches maximum. We explore the potentiality of Xμmax as a useful observable to infer the mass compositi…
Carbonyl compounds of Rh, Ir, and Mt: electronic structure, bonding and volatility
2020
With the aim to render assistance to future experiments on the production and investigation of chemical properties of carbonyl compounds of element 109, Mt, calculations of the molecular properties of M(CO)4 and MH(CO)4, where M = Rh, Ir, and Mt, and of the products of their decomposition, M(CO)3 and MH(CO)3, were performed using relativistic Density Functional Theory and Coupled-Cluster methods implemented in the ADF, ReSpect and DIRAC software suites. According to the results, MH(CO)4 should be formed at experimental conditions from the M atom with a mixture of CO and He gases. The calculated first M–CO bond dissociation energies (FBDE) of Mt(CO)4 and MtH(CO)4 turned out to be significant…
A multi-scale area-interaction model for spatio-temporal point patterns
2018
Models for fitting spatio-temporal point processes should incorporate spatio-temporal inhomogeneity and allow for different types of interaction between points (clustering or regularity). This paper proposes an extension of the spatial multi-scale area-interaction model to a spatio-temporal framework. This model allows for interaction between points at different spatio-temporal scales and the inclusion of covariates. We fit the proposed model to varicella cases registered during 2013 in Valencia, Spain. The fitted model indicates small scale clustering and regularity for higher spatio-temporal scales.
Experimental-Like Affinity Constants and Enantioselectivity Estimates from Flexible Docking
2012
Experimental-like affinity constants and enantioselectivity estimates, not predicted so far computationally, were obtained using a novel flexible modeling/docking combined strategy. The S- and R-warfarin-human serum albumin (HSA, site I) complexes were used as an interaction model. The process for a verified estimation includes the following: (i) ionized open chain forming at physiological pH (a recent focus); (ii) conformational search (molecular mechanics and Monte Carlo methods); (iii) rigid protein-flexible ligand docking (GlideXP) generating low energy paired S- and R-poses; (iv) graphical comparison against the X-ray crystal structure (unsatisfactory verification step); (v) quantum po…
Testing Hadronic Interactions at Ultrahigh Energies with Air Showers Measured by the Pierre Auger Observatory
2016
Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (ECM=110-170 TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory. The average hadronic shower is 1.33±0.16 (1.61±0.21) times larger than predicted using the leading LHC-tuned models EPOS-LHC (QGSJetII-04), with a corresponding excess of muons.
Interactions, spillovers de connaissance et croissance des villes européennes. Faut-il préférer la géographie, le climat institutionnel ou les réseau…
2013
Knowledge spillovers within urban economies are also sources of spillovers between cities. We examine how knowledge spillovers influenced the economic growth of 82 European metropolises over the 1990-2005 period. We model knowledge spillovers between cities on the basis of five specific interaction patterns based on geography, networks of multinational firms in advanced services, institutional climate and two combinations of these factors. Spatial models are estimated to detail the effects of growth factors in terms of spillovers and externalities. We show that spillovers are local rather than global and that interactions among cities accelerate the convergence process based on gross value …