Deciphering the rotational spectrum of the first excited torsional state of propylene oxide

The first excited torsional state of the chiral molecule propylene oxide, CH3C2H3O, is investigated from millimeter up to sub-millimeter wavelengths (75–950 GHz). vibrational mode υ24, analysed using programs ERHAM and XIAM. Rotational constants tunneling parameters are provided, a description A-E splittings due internal rotation given. Furthermore, potential barrier height rotation, V3, determined be V3=898.6611(894)cm-1. Our results compared with quantum chemical calculations literature values. We present line list dense spectrum oxide in (sub-) range. will useful for further studies molecules vibrationally states enable astronomers search rotational transitions originating υ24 interstellar space.