The dipole bound excited state of CCNH2− increases the likelihood for detection of this anion in the interstellar medium (ISM). There have been many different anions discovered in the ISM over the past decade starting in 2006 with the detection of C6H− followed by the discovery of 5 others: C4H−, C8H−, CN−, C3H−, and C5N−. The discovery of the anions shows that they are present in various places throughout the ISM. However, it is not completely known as to how or why these anions form. The most likely formation mechanism is through a dipole bound excited state. CCNH2− is an anion whose corresponding neutral radical has a very large dipole bound moment, which makes it a suitable molecule to study. The neutral radical can capture the extra electron in the dipole bound state, and the anion can relax back down to the closed-shell, ground electronic state. Quantum chemistry is one of the best methods to finding out more information regarding these molecules. By doing computations on the ground state and the dipole bound excited state of CCNH2−, it can be determined whether or not either of these states can be observed in the ISM. A quartic force field can be constructed based on the quantum chemical energies calculated. The vibrational frequencies and spectroscopic constants are subsequently produced and can be used to detect the anion in the ISM by telescopic observation. This could lead to the discovery of other naturally occurring anions throughout the ever expanding universe.

Rovibronic quantum chemical analysis of the anion CCNH2−

253rd National Meeting (2017)

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