Theoretical Electronic and Rovibrational Studies for Anions of Interest to the DIBs
arXiv:1308.3507 · doi:10.1017/S1743921313016098
Abstract
The dipole-bound excited state of the methylene nitrile anion (CH2CN-) has been suggested as a candidate carrier for a diffuse interstellar band (DIB) at 803.8 nm. Its corresponding radical has been detected in the interstellar medium (ISM), making the existence for the anion possible. This work applies state-of-the-art ab initio methods such as coupled cluster theory to reproduce accurately the electronic excitations for CH2CN- and the similar methylene enolate anion, CH2CHO-. This same approach has been employed to indicate that 19 other anions may possess electronically excited states, five of which are valence in nature. Concurrently, in order to assist in the detection of these anions in the ISM, work has also been directed towards predicting vibrational frequencies and spectroscopic constants for these anions through the use of quartic force fields (QFFs). Theoretical rovibrational work on anions has thus far included studies of CH2CN-, C3H-, and is currently ongoing for similar systems.
5 pages, 2 tables; to appear in "The Diffuse Interstellar Bands" (proceedings of IAU Symposium No. 297, Eds. J. Cami and N. Cox); contributed talk
References in corpus (3)
- High-Accuracy Quartic Force Field Calculations for the Spectroscopic Constants and Vibrational Frequencies of 1 ^1A' l-C3H-: A Possible Link to Lines Observed in the Horsehead Nebula PDR
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- The Possible Interstellar Anion CH2CN-: Spectroscopic Constants, Vibrational Frequencies, and Other Considerations