Semi-classical dynamics studies of the photodissociation of ICN− and BrCN−

Opoku-Agyeman, Bernice

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https://hdl.handle.net/2142/96936 Copy

Description

Title

Semi-classical dynamics studies of the photodissociation of ICN− and BrCN−

Author(s)

Opoku-Agyeman, Bernice

Contributor(s)

McCoy, Anne B.

Issue Date

2017-06-20

Keyword(s)

Multiple potential energy surfaces

Abstract

We present the results of surface hopping studies of the photodissociation of ICN$^{-}$ and BrCN$^{-}$ following UV and visible excitations to states that can dissociate to X$^{-}$ + CN or X$^{*}$ + CN$^{-}$ (X = I or Br). Based on previous quantum dynamics studies carried out on the anions, the electronic states that are accessed by the initial UV or visible excitation were found to be coupled, and both photoproducts were observed in the dissociation process. The calculated branching ratios indicated stronger non-adiabatic interactions between the adiabatic electronic states in BrCN$^{-}$ than in ICN$^{-}$.footnote{B. Opoku-Agyeman, A. S. Case, J. H. Lehman, W. Carl Lineberger and A. B. McCoy, textit{J. Chem Phys.} textbf{141}, 084305 (2014).}footnote{A. S. Case, A. B. McCoy, W. C. Lineberger, textit{J. Phys. Chem. A}, textbf{117}(50), 13310(2013).}footnote{A. S. Case, E. M. Miller, J. P. Martin, Y. J. Lu, L. Sheps, A. B. McCoy, W. C. Lineberger, textit{Angew. Chem., Int. Ed.} textbf{51}(11), 2651 (2012).}_x000d_ In this work, we employ Tully's surface hopping algorithmfootnote{J. C. Tully, textit{J. Chem Phys.} textbf{93}, 1061 (1990)} implemented in classical dynamics simulations to investigate the fragmentation processes of these anions. We calculate the branching ratios and the partitioning of the energies among the various degrees of freedom during the dynamics. The results of the surface hopping algorithm are then compared to the reported quantum dynamics results after which the surface hopping approach can then be applied to investigate the dynamics of argon clusters of the ICN$^{-}$ and BrCN$^{-}$. In addition to comparison between the quantum and classical dynamics calculations, preliminary results for the semi-classical calculations on the ICN$^{-}$ show that during the dissociation process, some of the anions live longer than others. Once the anions are solvated, we expect the presence of the argon atoms to stabilize the complexes as reported in previous work, resulting in longer lifetimes. Since experimental studies carried out on the solvated anions show the existence of recombined products even for clusters as small as ICN$^{-}$(Ar) or ICN$^{-}$(Ar)$_2$, when the clusters are initially excited with visible or UV radiations, respectively,$^{b c}$ the observations of these long-lived anions provide a step towards understanding the dynamics processes that lead to the recombined products in the clusters.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/96936

DOI

https://doi.org/10.15278/isms.2017.TG07

Copyright and License Information

Copyright 2017 Bernice Opoku-Agyeman

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