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application/vnd.openxmlformats-officedocument.presentationml.presentation ![]() | Presentation | Microsoft PowerPoint 2007 |
application/pdf ![]() | Abstract |
Description
Title: | EVALUATING VPT2 SCHEMES FOR ACCURATE AUTOMATED THERMOCHEMISTRY AND SPECTROSCOPY FOR NON-COVALENT SYSTEMS |
Author(s): | Welch, Bradley |
Contributor(s): | Bross, David H.; Ruscic, Branko ; Quintas Sánchez, Ernesto ; Dawes, Richard |
Subject(s): | Electronic structure, potential energy surfaces |
Abstract: | High level computational thermochemical protocols take an additive approach to computing the total energy of a molecular system. For small systems, components related to the electronic structure can be systematically converged using methods such as coupled-cluster theory at the complete basis limit. The vibrational level pattern (and at 0 K the zero-point energy, ZPE) yields a relatively large contribution and is thus a possible source of significant error. An inaccurate ZPE leads to poor quantities such as enthalpies of formation and hence interpretations in kinetics and dynamics. As a result an accurate determination of this one term is critical and the focus of this talk. Accurate anharmonic models such as VPT2 and VCI exist for semi-rigid molecules in the gas phase. Non-covalent systems are also of importance in a wide range of areas. The VPT2 model has not been applied as widely to non-covalent systems and questions remain as to its general applicability. Here, a screening of low-cost implementations of VPT2 calculations were performed for a series of vdW systems as large as Benzene-Ar. The screening was done with an automated thermochemical protocol. Comparisons are made with full-dimensional variational calculations using global potential energy surfaces, and to experimental data where available. |
Issue Date: | 2019-06-19 |
Publisher: | International Symposium on Molecular Spectroscopy |
Genre: | Conference Paper / Presentation |
Type: | Text |
Language: | English |
URI: | http://hdl.handle.net/2142/104435 |
DOI: | 10.15278/isms.2019.WD05 |
Rights Information: | Copyright 2019 Bradley Welch |
Date Available in IDEALS: | 2019-07-15 2020-01-25 |