New Perspectives on an Old Issue: A Comparative MS-CASPT2 and OM2-MRCI Study of Polyenes and Protonated Schiff Bases
| Autor: | Irina Dokukina, Oliver Weingart, Christel M. Marian |
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| Rok vydání: | 2017 |
| Předmět: |
chemistry.chemical_classification
010304 chemical physics Double bond Chemistry Ab initio Protonation General Medicine Light perception 010402 general chemistry 01 natural sciences Biochemistry 0104 chemical sciences Bond length Computational chemistry Excited state 0103 physical sciences Physical and Theoretical Chemistry |
| Zdroj: | Photochemistry and Photobiology. 93:1345-1355 |
| ISSN: | 0031-8655 |
| DOI: | 10.1111/php.12833 |
| Popis: | Polyenic systems are involved in light perception of numerous living organisms. Although a π-conjugated backbone is a common feature of all polyenes, their photophysics may vary. We provide a comparative quantum-mechanical study of low lying S1 and S2 excited states in short (3-5 double bonds) symmetric all-trans linear polyenes and corresponding protonated Schiff bases. In our investigation, we use the well-established ab initio multireference CASPT2 approach and benchmark the efficient semi-empirical OM2-MRCI approach against it. For all protonated Schiff bases, MS-CASPT2 results in two distinct S1 minima with inverted and non-inverted bond length pattern, respectively. We find, that OM2-MRCI is a computationally affordable and reliable alternative to MS-CASPT2 for investigations of polyenic systems, particularly when highly demanding calculations (e.g., excited state dynamics) need to be performed. This article is protected by copyright. All rights reserved. |
| Databáze: | OpenAIRE |
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