title: Ab initio study of the barriers to methyl torsion and torsional frequencies of acetyl molecules.
abstract: A wide range of ab initio and hybrid density functional methods and basis sets have been employed to calculate the barriers to methyl internal rotation in a range of molecules with the acetyl moiety. Comparison is made of the computed torsional frequency with the experimental torsional frequency, nu(obs), for each molecule. With the MP2/6-311+G(3df,2p) combination of method and basis set, the agreement is better than 4 cm-1 for most of the molecules, where nu(obs) or the V3 barrier is well-determined experimentally.
authors.affiliation: Faculty of Life Sciences, Carnelley Building, University of Dundee, Dundee DD14HN, Scotland, UK. s.bell@dundee.ac.uk
authors.forename: Stephen
authors.initials: S
authors.lastname: Bell
mesh_terms: D000079:Acetaldehyde / Q000737:chemistry; D000085:Acetates / Q000737:chemistry; D000096:Acetone / Q000737:chemistry; D000098:Acetophenones / Q000737:chemistry; D000114:Acetylene / Q000737:chemistry; D002074:Butanones / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D003486:Cyanides / Q000737:chemistry; D017953:Isocyanates / Q000737:chemistry; D017879:Isothiocyanates / Q000737:chemistry; D007659:Ketones / Q000737:chemistry; D008872:Microwaves; D008968:Molecular Conformation; D012984:Software; D013055:Spectrophotometry, Infrared / Q000379:methods*
chemical_list: D000085:Acetates; D000098:Acetophenones; D002074:Butanones; D002712:Chlorides; D003486:Cyanides; D017953:Isocyanates; D017879:Isothiocyanates; D007659:Ketones; C108790:acetyl isothiocyanate; D000096:Acetone; C005222:methylethyl ketone; C057920:3-buten-2-one; D000079:Acetaldehyde; C412887:acetyl bromide; D000114:Acetylene; C081124:acetyl chloride; C038699:acetophenone