Comprehensive Quantum Chemical Analysis of the Microwave and Infrared Spectra of Cyclopropenone

Rovibrational configuration interaction theory including up to sextuple excitations has been used to study, simulate, and analyze the rotational spectrum and low-lying rovibrational states of cyclopropenone. This molecule has been repeatedly discovered in space, experimentally investigated in the laboratory, and was subject to theoretical studies. However, a comprehensive ab initio study of its microwave spectrum and rovibrational transitions in the far-infrared region has not yet been provided. A line list with about 3 million rovibrational transitions has been generated, covering temperature ranges between 10 and 300 K. Furthermore, this study reports highly accurate geometrical parameters, fundamental vibrational transitions, and spectroscopic constants. All calculations rely on a multidimensional potential energy surface including up to 4-mode coupling terms being obtained from explicitly correlated coupled-cluster theory including core correlation effects and estimates for high-order excitations. The computed results were validated against available experimental data, showing excellent agreement for most properties.