Rotational spectroscopy and ISM search CPCA

The spectroscopic study was supported by high-level theoretical calculations which were used in the identification of the vibrational excited states of cyclopropanecarboxaldehyde. The analysis of the rotational spectrum of cyclopropanecarboxaldehyde allowed us to obtain accurate rotational parameters for the ground state of both cis and trans isomers, which were used to derive predictions sufficiently reliable up to 500GHz.

In addition to the ground states, we identified twelve and six vibrationally excited states for the trans and cis isomers, respectively, including fundamental modes, multiple excitation quanta and combination states. We found that the gas phase concentration of the trans isomer is almost 1.2 times larger than that for the cis one. The new experimental rotational parameters were employed to search for cyclopropanecarboxaldehyde in the warm molecular clouds Orion KL and Sgr B2(N) using the spectral surveys captured by ALMA (Orion) and IRAM 30m (Sgr) at 1mm and 3mm, respectively.