Journal Article

PreJuSER-15678

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Azomethane: Nonadiabatic Photodynamical Simulations in Solution

Ruckenbauer, M. ; Barbatti, M. ; Sellner, B. ; Müller, T.FZJ* ; Lischka, H.

2010
Soc. Washington, DC

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Please use a persistent id in citations: doi:10.1021/jp108844g

Abstract: The nonadiabatic deactivation of trans-azomethane starting from the nπ* state has been investigated in gas phase, water, and n-hexane using an on-the-fly surface-hopping method. A quantum mechanical/molecular mechanics (QM/MM) approach was used employing a flexible quantum chemical level for the description of electronically excited states and bond dissociation (generalized valence bond perfect-pairing complete active space). The solvent effect on the lifetime and structural parameters of azomethane was investigated in detail. The calculations show that the nonadiabatic deactivation is characterized by a CNNC torsion, mainly impeded by mechanic interaction with the solvent molecules. The similar characteristics of the dynamics in polar and nonpolar solvent indicate that solvent effects based on electrostatic interactions do not play a major role. Lifetimes increase by about 20 fs for both solvents with respect to the 113 fs found for the gas phase. The present subpicosecond dynamics also nicely show an example of the suppression of C-N dissociation by the solvent cage.

Keyword(s): Azo Compounds: chemistry (MeSH) ; Hexanes: chemistry (MeSH) ; Models, Molecular (MeSH) ; Photochemistry (MeSH) ; Quantum Theory (MeSH) ; Solutions (MeSH) ; Solvents: chemistry (MeSH) ; Water: chemistry (MeSH) ; Azo Compounds ; Hexanes ; Solutions ; Solvents ; n-hexane ; azomethane ; Water ; J

Note: This work was supported by the Austrian Science Fund within the framework of the Special Research Programs F16 (Advanced Light Sources) and F41 (ViCoM) and Project P18411-N19. The authors are also thankful for the technical support and computer time at the VSC-Vienna Scientific Cluster (Project nos. 70019 and 70151) and at the Luna-Cluster of the Department of Scientific Computing, University of Vienna. Displays of molecular structures were made with VMD. VMD was developed with NTH support by the Theoretical and Computational Biophysics group at the Beckman Institute, University of Illinois at Urbana-Champaign (http://www.ks.uiuc.edu/Research/vmd/).

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Contributing Institute(s):

1. Jülich Supercomputing Centre (JSC)

Research Program(s):

1. Scientific Computing (FUEK411) (FUEK411)
2. 411 - Computational Science and Mathematical Methods (POF2-411) (POF2-411)

Appears in the scientific report 2010

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