Publication

1st Principles Molecular-Dynamics Calculation of the Structure and Acidity of a Bulk Zeolite

Alfredo Pasquarello
1994
Journal Articles

Abstract

Local density functional theory within the framework of the Car-Parrinello method has been used to study the structural parameters and the energetics of offretite, when a Si4+ ion is substituted by (Al3+, H+). The calculations have been performed on a periodically repeated unit cell with 54 atoms and a proton. in agreement with previous cluster calculations, we conclude that the sites with the lowest (Al, H)/Si substitution energies are also those with the largest proton affinity. In addition a correlation previously reported between acidity and Al-O-Si bond angles is confirmed.

Official source

https://infoscience.epfl.ch/entities/publication/bffb9650-e4a5-455c-8ba3-3683ed05fe99

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

Alfredo Pasquarello
1994
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/bffb9650-e4a5-455c-8ba3-3683ed05fe99

About this result

Related concepts (25)

Gibbs free energy

In thermodynamics, the Gibbs free energy (or Gibbs energy as the recommended name; symbol ) is a thermodynamic potential that can be used to calculate the maximum amount of work, other than pressure-volume work, that may be performed by a thermodynamically closed system at constant temperature and pressure. It also provides a necessary condition for processes such as chemical reactions that may occur under these conditions. The Gibbs free energy is expressed as where p is pressure, T is the temperature, U is the internal energy, V is volume, H is the enthalpy, and S is the entropy.

Internal energy

The internal energy of a thermodynamic system is the energy contained within it, measured as the quantity of energy necessary to bring the system from its standard internal state to its present internal state of interest, accounting for the gains and losses of energy due to changes in its internal state, including such quantities as magnetization. It excludes the kinetic energy of motion of the system as a whole and the potential energy of position of the system as a whole, with respect to its surroundings and external force fields.

Lead–acid battery

The lead–acid battery is a type of rechargeable battery first invented in 1859 by French physicist Gaston Planté. It is the first type of rechargeable battery ever created. Compared to modern rechargeable batteries, lead–acid batteries have relatively low energy density. Despite this, their ability to supply high surge currents means that the cells have a relatively large power-to-weight ratio. These features, along with their low cost, make them attractive for use in motor vehicles to provide the high current required by starter motors.

Related publications (3)

1st Principles Molecular-Dynamics Calculation of the Structure and Acidity of a Bulk Zeolite

Chat with Graph Search

The charge density of urea from synchrotron diffraction data

Multi-Scale B-Spline Snakes for General Contour Detection

Generalized-gradient approximations to density-functional theory: A comparative study for atoms and solids