Abstract
Photochemical reactions of carbonyl molecules such as aldehydes, ketones, carboxylic acids and other species are among the largest and most important families of light-induced organic processes. The dynamical mechanisms of these processes are not well understood for relatively large molecules, and for carbonylic molecules in a solvent, or in an aggregated phase. In this chapter, we describe progress in the understanding of photochemistry in relatively large carbonylic molecules, in clusters of such molecules, and in the molecules in host clusters. The prime tool of investigation are classical molecular dynamics simulations using on the fly semi-empirical quantum chemical potential energy surfaces that seem capable of describing the excited states. Thus, we propose a methodology for treating such processes. In this chapter, the photochemistry of two carbonylic molecules, namely pentanal and cis-pinonic acid, is discussed. Some of the main findings on the mechanisms of the processes are: 1) Norrish type I and Norrish type II reactions occurs in all systems. The reactions take place on the triplet state surface. 2) There is a large difference in yields for different channels, for the bare pentanal vs. pentanal embedded in a pentanal cluster. 3) The pentanal cluster leads to cross-molecular reactions between different pentanal molecules, and therefore enlarges the variety of products obtained. 4) Water affects the photochemistry of pinonic only by varying the yields of the different pathways, without being involved directly in reactions. It is suggested, that the approach used in this study is applicable on a wide range photochemical reactions of organic compounds, and can predict mechanisms and time scales of these reactions.
Original language | English |
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Title of host publication | Advances in Chemical Physics |
Publisher | wiley |
Pages | 1-22 |
Number of pages | 22 |
Volume | 159 |
ISBN (Electronic) | 9781119096276 |
ISBN (Print) | 9781119096269 |
DOIs | |
State | Published - 1 Apr 2016 |
Bibliographical note
Publisher Copyright:© 2016 by John Wiley & Sons, Inc. All rights reserved.
Keywords
- Carbonyl group
- Clusters
- Cross-molecular reactions
- Molecular dynamics
- Norrish type I
- Norrish type reactions
- Photochemistry
- Semiempirical potential energy surfaces
- Triplet states
- Unimolecular reactions