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Updated: Dec 30, 2025

Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Rich Collection of n-Propylamine and Isopropylamine Conformers: Rotational Fingerprints and State-of-the-Art Quantum
Mattia Melosso1, Alessio Melli1, Lorenzo Spada1,2
1Dipartimento di Chimica "Giacomo Ciamician" , Università di Bologna , Via Selmi 2 , 40126 Bologna , Italy.
Abstract:
The conformational isomerism of isopropylamine and n-propylamine has been investigated by means of an integrated strategy combining high-level quantum-chemical calculations and high-resolution rotational spectroscopy. The equilibrium structures (and thus equilibrium rotational constants) as well as relative energies of all conformers have been computed using the so-called "cheap" composite scheme, which combines the coupled-cluster methodology with second-order Møller-Plesset perturbation theory for extrapolation to the complete basis set. Methods rooted in the density functional theory have been instead employed for computing spectroscopic parameters and for accounting for vibrational effects. Guided by quantum-chemical predictions, the rotational spectra of isopropylamine and n-propylamine have been investigated between 2 and 400 GHz with Fourier transform microwave and frequency-modulation millimeter/submillimeter spectrometers. Spectral assignments confirmed the presence of several conformers with comparable stability and pointed out possible Coriolis resonance effects between some of them.
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