Date

2018

Major

Chemistry (B.S.)

Document Type and Release Option

Thesis (open access)

Faculty Mentor

Dr. Ryan C. Fortenberry

Abstract

The search for possible, natural, noble gas molecules has led to quantum chemical, spectroscopic analysis of NeCCH+, ArNH+ ArCCH+, and ArCN+. Each of these systems have been previously shown to be a stable minimum on its respective potential energy surface. However, no spectroscopic data are available for laboratory detection or interstellar observation of these species, and the interstellar medium may be the most likely place, in nature, where these noble gas cations are found. The bent shape of NeCCH+ is confirmed here with a fairly large dipole moment and a bright C -- H stretching frequency at 3101.9 cm-1. Even if this molecule is somewhat unstable, it is likely observable now that the spectral ranges of where to look have been established. ArCCH+ is much more stable but has dim double harmonic intensities for the vibrational fundamentals and a dipole moment below 0.5 D making its rotational transitions likely buried in the astronomical weeds. Even so, ArCCH+ cannot be excluded as a possibility in laboratory experiments of hydrocarbons in argon-rich environments. ArCN+, on the other hand, has a dipole moment of greater than 3.5 D, an observable C -- N stretching fundamental at 2189.6 cm-1 (4.567 microns), and a viable formation pathway through HCN, a highly-abundant interstellar molecule. Consequently, the result of this work provides novel high-level spectroscopic data to aid in the search for covalently bound noble gas molecules in observable regions of outer space.

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