Predicting Catalysis: Understanding Ammonia Synthesis from First-Principles Calculations

Ammonia synthesis from first-principles calculations.

The rate of ammonia synthesis over a nanoparticle ruthenium catalyst can be calculated directly on the basis of a quantum chemical treatment of the problem using density functional theory. We compared the results to measured rates over a ruthenium catalyst supported on magnesium aluminum spinel. When the size distribution of ruthenium particles measured by transmission electron microscopy was u...

Vibrational energy levels of ammonia-type molecules from first principles calculations

The vibrational spectra of ammonia and the hydronium ion, including both their symmetric and asymmetric isotopomers, are calculated variationally using potential energy surfaces obtained with the latest methods of electronic structure calculation. The centrally bound ammonia-type molecules are interesting systems to study, due to the combination of the large-amplitude inversion motion and five ...

Tight-binding Hamiltonian from first-principles calculations

The tight-binding method attempts to represent the electronic structure of condensed matter using a minimal atomic-orbital like basis set. To compute tight-binding overlap and Hamiltonian matrices directly from first-principles calculations is a subject of continuous interest. Usually, first-principles calculations are done using a large basis set or long-ranged basis set (e.g. muffin-tin orbit...

Magnetism of Chromia from First-Principles Calculations

First Principles Calculations

Calculations of the linestrengths and transition frequencies of the forbidden pure rotational spectrum of Hz in the vibrationally excited v2 state are presented. These transitions occur in the far-infrared region, and their observation may be complicated by vi u2 difference transitions. Examples of these are also given. Forbidden rovibrational transition frequencies and linestrengths have also ...