Far-IR spectra, barriers to internal-rotation, <script type="math/tex">r_{0}</script> structural parameters and ab initio calculations of chloromethyl methyl ether

Guirgis, G.A.; van der Veken, B.J.; Liu, Jian; Durig, J.R.

doi:10.1016/S0584-8539(09)91008-X

Title

Far-IR spectra, barriers to internal-rotation, $r_{0}$ structural parameters and ab initio calculations of chloromethyl methyl ether

Author

Guirgis, G.A.

van der Veken, B.J.

Liu, Jian

Durig, J.R.

Abstract

The far-IR spectra from 350 to 50 cm(-1) of gaseous chloromethyl methyl ether, CICH2OCH3, along with three of the deuterium isotopomers, have been recorded at a resolution of 0.10 cm(-1). The fundamental asymmetric torsional and methyl torsional modes are extensively mixed and have been observed at 180 and 133 cm(-1), respectively. An estimate is given for the potential function governing the asymmetric torsion. On the basis of a one-dimensional model the barrier to internal rotation of the methyl moiety is determined to be 556 +/- 5 cm(-1) (1.59 +/- 0.01 kcal mol(-1)). Utilizing previously reported rotational constants for seven isotopomers, r(0) structural parameters are determined. The heavy atom parameters (distances in angstroms angles in degrees) are: r(C-1-Cl) = 1.818 +/- 0.003; r(C-1-O)=1.371 +/- 0.004; r(C-2-O) = 1.430 +/- O.OO1; measured angle ClC1O = 113.01 +/- 0.07; measured angle C1OC2 = 114.03 +/- 0.10 and dihedral ClC1OC2 = 70.20 +/- 0.15. A complete vibrational assignment is given for the ClCD2OCD3 molecule. The fundamental vibrational frequencies, barrier to internal rotation and structural parameters which have been obtained experimentally are compared with those obtained from ab initio Hartree-Fock calculations employing the 3-21G* and 6-31G* basis sets along with the 6-31G* basis set with electron correlation at the MP2 level. All of these results are discussed and compared with the corresponding quantities obtained for some similar molecules.

Language

English

Source (journal)

Spectrochimica acta: part A: molecular spectroscopy. - Oxford, 1967 - 1994

Publication

Oxford : 1993

ISSN

0584-8539

DOI

10.1016/S0584-8539(09)91008-X

Volume/pages

49 :13-14 (1993) , p. 1947-1965