Dipole Bound Excited States of Polycyclic Aromatic Hydrocarbons containing Nitrogen and their Relation to the Interstellar Medium

Polycyclic aromatic hydrocarbons (PAHs) are the most abundant type of molecule present in the interstellar medium (ISM). It has been hypothesized that nitrogen replacement within a ring is likely for PAHs present in the ISM. Additionally, electrons, protons, and hydrogen atoms are readily added to or removed from PAHs creating a truly diverse set of chemistries in various interstellar regions. The presence of a nitrogen within a PAH (called a PANH herein) that is additionally dehydrogenated leads to a neutral radical with a large dipole moment. It has recently been shown through the use of high-level quantum chemical computations for small molecules that the corresponding closed-shell anions support electronically excited states within a dipolebound formalism as a result of the interaction between the loosely bound excited electron and the dipole moment of the neutral radical. We are extending this methodology to larger molecules, PANHs in this case. If a dipole-bound excited state of a PANH anion exists, it could possess unique features that could shed light on various unresolved interstellar spectra potentially including even the diffuse interstellar bands. Thesis Mentor:________________________ Dr. Ryan C. Fortenberry Honors Director:_______________________ Dr. Steven Engel April 2014 Chemistry Department University Honors Program Georgia Southern University