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application/vnd.openxmlformats-officedocument.presentationml.presentation ![]() | Presentation | Microsoft PowerPoint 2007 |
application/pdf ![]() | Abstract |
Description
Title: | CONSTRUCTION OF POTENTIAL ENERGY SURFACES FOR THEORETICAL STUDIES OF SPECTROSCOPY AND DYNAMICS |
Author(s): | Dawes, Richard |
Subject(s): | Plenary |
Abstract: | Accurate potential energy surfaces (PESs) combined with methods to solve the Schrレdinger equation for the nuclei permit the prediction and interpretation of various types of molecular spectra and/or dynamics. Part of this talk describes the development of a PES generator (software code) which uses parallel processing on High-Performance Computing (HPC) clusters to construct PESs automatically. Thousands of ab initio data are computed at geometries chosen by an algorithm and fit to a functional form. This strategy is particularly successful when the electronic structure is robustly convergent (such as vdWs systems composed of two closed-shell monomers). Results for a few of such systems [e.g., (CO)$_{2}$, (NNO)$_{2}$, CO$_{2}$-CS$_{2}$, (OCS)$_{2}$] will be presented. The electronic structure of molecules is difficult to describe continuously across global reactive PESs since it changes qualitatively as bonds are formed and broken along reaction coordinates. I will discuss a high-level ab initio method (GDW-SA-CASSCF/MRCI) designed to allow the electronic wavefunction to smoothly evolve across the PES and provide an accurate and balanced description of the various regions. These methods are combined to study a number of small gas-phased molecules from the areas of atmospheric, combustion and interstellar chemistry including a large variational calculation of all the bound vibrational states of ozone and the photodissociation dynamics of the simplest Criegee intermediate (CH$_{2}$OO). |
Issue Date: | 24-Jun-15 |
Publisher: | International Symposium on Molecular Spectroscopy |
Citation Info: | ACS |
Genre: | Conference Paper / Presentation |
Type: | Text |
Language: | English |
URI: | http://hdl.handle.net/2142/79177 |
Date Available in IDEALS: | 2016-01-05 |