title: A priori predictions of the rotational constants for protonated formaldehyde and protonated methanol.
abstract: Protonated formaldehyde and protonated methanol are candidate interstellar molecules and models for classes of protonated oxygen compounds.  Ab initio molecular orbital theory has been used to compute rotational constants to guide spectroscopic searches both in the laboratory and in space.  The ab initio results are empirically corrected to account for systematic deficiencies in the theory and zero-point vibrational effects; they are expected to be accurate to approximately +/-2%.  For H2COH+ the resultant constants are (in GHz) A = 194.3, B = 34.28, and C = 29.14; for H3COH2+ A = 103.7, B = 21.18, and C = 20.30.
authors.affiliation: Molecular Research Institute, Palo Alto, California 94304, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: DeFrees
authors.forename: A D
authors.initials: AD
authors.lastname: McLean
mesh_terms: D055580:Astronomical Phenomena; D001256:Astronomy; D005118:Extraterrestrial Environment; D005557:Formaldehyde / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry*; D008958:Models, Molecular; D011522:Protons; D012399:Rotation
chemical_list: D011522:Protons; D005557:Formaldehyde; D000432:Methanol