Stable negative ions and shape resonances in a series of organic molecules

We report on the theoretical determination of low-lying shape resonances in a selected set of seven molecules. The finite element discrete model method is used and the absolute differences between calculated and experimental values, where known, are (sic)0.15 eV for the resonances lowest in energy. Difficulties expected with the higher calculated values are discussed. This article reports results for ortho-benzyne, benzene, naphthalene, anthracene, styrene, formamide, and acetamide. Comparisons are made with a few other calculations, again where available. (C) 2013 AIP Publishing LLC.