Deciphering the Rotational Spectrum of the First Excited Torsional State of Propylene Oxide

Abstract

The first excited torsional state of the chiral molecule propylene oxide, $\mathrm{C}{\mathrm{H}}_3{\mathrm{C}}_2{\mathrm{H}}_3\mathrm{O}$, is investigated from millimeter up to sub-millimeter wavelengths (75-950 GHz). The first excited vibrational mode of propylene oxide, ${\upsilon }_{24}$, is analysed using the programs ERHAM and XIAM. Rotational constants and tunneling parameters are provided, and a description of the A-E splittings due to internal rotation is given. Furthermore, the potential barrier height to internal rotation $V_3$ is determined to be $V_3=894.5079(259)\mathrm{c}{\mathrm{m}}^{-1}$ . Our results are compared with quantum chemical calculations and literature values. We present a line list of the dense spectrum of the first excited torsional state of propylene oxide in the (sub-)millimeter range. Our results will be useful for further studies of chiral molecules in vibrationally excited states, and will enable astronomers to search for rotational transitions originating from ${\upsilon }_{24}$ of propylene oxide in interstellar space.

Electronic pre-print version of the pre-submission. IMPORTANT: changes in parts of the spectral analysis with XIAM emerged during the peer-reviewing procedure! The original peer-reviewed publication and Supplementary Material (SI) are available under the DOI: 10.1016/j.jms.2021.111445

References in corpus (3)

• Discovery of the Interstellar Chiral Molecule Propylene Oxide (CH${}_3$CHCH${}_2$O)
• Laboratory blueprints for interstellar searches of aromatic chiral molecules: rotational signatures of styrene oxide
• Accidental Interaction in the Torsional Spectrum of Singly Deuterated Hydrogen Peroxide HOOD