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Loss of a C2H n fragment from pyrene and circumcoronene

  • Charles W. BauschlicherJr.Email author
  • Alessandra Ricca
Regular Article
Part of the following topical collections:
  1. Shavitt Memorial Festschrift Collection

Abstract

Reactions at the edge of pyrene and circumcoronene are studied using the B3LYP approach in conjunction with the 4-31G and 6-31G** basis sets. The loss of a C2H n fragment from the edge of either molecule requires more than 7 eV, which is much larger than for the loss of an H atom. Some paths can be broken down into a series of less energetic steps, but this does not change the overall endothermicity of the process. The exception is a path where a hydrogen atom adds to pyrene or circumcoronene. The resulting molecule rearranges to have a \(\hbox {C}_2\hbox {H}_2\) side group, which is subsequently lost. This process has an overall endothermicity of only about 2.5 eV. This path is actually less endothermic than the loss of an H atom from the same species.

Keywords

DFT Polycyclic aromatic hydrocarbon Loss of C2Hn 

Notes

Acknowledgments

AR thanks NASA’s Astrophysics Theory and Fundamental Physics (ATFP) (NNX09AD18G) program for its generous support of this work.

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Copyright information

© Springer-Verlag Berlin Heidelberg (outside the USA) 2014

Authors and Affiliations

  1. 1.Entry Systems and Technology DivisionNASA Ames Research CenterMoffett FieldUSA
  2. 2.Carl Sagan CenterSETI InstituteMountain ViewUSA

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