The structures and vibrational frequencies of a series of aliphatic ethers obtained using the spectroscopic potential SPASIBA

Abstract

The SPASIBA potential energy function has been extended to include linear ethers, in order to investigate biomolecules related to saccharides. The parameters of the potential energy function were derived from minimization of the average error between the observed structures, conformational energy differences, vibrational frequencies and the predicted quantities for a series of aliphatic ethers, including some deuterated analogues. For several molecules the dipole moment was also calculated and compared with experimental or ab initio values. The molecules under investigation are dimethyl ether, trans and gauche forms of methyl ethyl ether, trans-trans and trans-gauche forms of diethyl ether, methyl isopropyl ether and ethyl isopropyl ether. A set of 32 independent force constants was found to be sufficient to correctly describe their structures, potential energy surfaces and vibrational frequencies. The average deviation between the predicted and observed frequencies is about 11 cm −1.