IDEA: Interface dynamics and energetics algorithm

Abstract

IDEA, interface dynamics and energetics algorithm, was implemented, in FORTRAN, under different operating systems to mimic dynamics and energetics of elementary events involved in interfacial processes. The code included a parallel elaboration scheme in which both the stochastic and the deterministic components, involved in the developed physical model, worked simultaneously. IDEA also embodied an optionally running VISUAL subroutine, showing the dynamic energy changes caused by the surface events, e.g., occurring at the gas-solid interface. Monte Carlo and ordinary differential equation system subroutines were employed in a synergistic way to drive the occurrence of the elementary events and to manage the implied energy flows, respectively. Biphase processes, namely isothermal and isobaric adsorption of carbon monoxide on nickel, palladium, and platinum surfaces, were first studied to test the capability of the code in modeling real frames. On the whole, the simulated results showed that IDEA could reproduce the inner characteristics of the studied systems and predict properties not yet experimentally investigated.

Structural and Kinetic DFT Characterization of Materials to Rationalize Catalytic Performance

“…Finally, it has been found that, oppositely to what experimentally observed for the cis-but-2-ene/trans-but-2-ene gas-phase order of stability, several 52T systems containing cis-but-2-ene resulted more stable than the analogous systems involving trans-but-2-ene isomer adsorbed on the same acidic -OH sites, confirming the basis role played by the local steric hindrance, in driving molecular adsorption properties and surface reactivity in confined spaces [78][79][80][81][82].…”

Molecular-Level Characterization of Heterogeneous Catalytic Systems by Algorithmic Time Dependent Monte Carlo

“…Therefore, specific local events are described with a high level of accuracy, and the approach is developed on a fully molecular-level base, revealing the inmost details of the process and suggesting criticisms to results obtained by more conventional modelling approaches [5,19].…”

“…Each of these elementary steps, including the null event, is characterized by an occurrence probability, which might be derived either from experimental or from quantum chemical (qc) calculation findings. Likewise, also the interactions between the various species adsorbed on the surface sites are characterized by adequate residence probabilities [5,9,10], which account for the steric hindrance of the adsorbed surface derivatives. Due to local interaction-potential changes, the surface-event occurrence probabilities are usually variable at the same time as the system is evolving.…”

“…With respect to this, it has to be stressed that the tdMC algorithms are not based, as the kinetic MC ones [13,14], on the dynamic interpretation of equilibrium results [15] but instead constitute non-equilibrium examples of algorithmic [16] and true-dynamic [17] MC approaches. The present application fields concern the CO adsorption/desorption processes on Group 10 metal surfaces [5], the hydrogenation of unsatured hydrocarbons and hydrocarbon mixtures [6][7][8][9][10]18] as well as the hydrogenation of nitro-derivatives [19] on metal surfaces and the but-2-ene isomerization on unsupported or metal-supported H-ZSM-5 zeolite catalysts. Each of these topics are discussed in Sect.…”

“…Time dependent Monte Carlo (tdMC) algorithms [3,4] have been designed and employed, as many other equilibrium and nonequilibrium Monte Carlo (MC) and Cellular Automata approaches [5], to adequately simulate kinetic details and reaction mechanisms of heterogeneous catalytic systems, in the aim to obtain (i) dynamic results fully comparable with those of corresponding experimental systems and, when possible, (ii) hints on experimental aspects not yet investigated [6,7]. The catalysis oriented tdMC algorithms, mainly employed in the simulation of hydrogenation processes, have been derived from the ZiffGulari-Barshad (ZGB) code [8], originally introduced to study the CO oxidation on metal surfaces, by including ''real-time'' dynamic functions.…”