J. S. Muenter

Electric Dipole Moment of Carbonyl Sulfide

The electric dipole moment of OCS has been determined by measuring pure Stark transitions with molecular‐beam electric resonance methods. The value obtained is 0.71521 ± 0.00020 D, which is in disagreement with a previous measurement of 0.7124 ± 0.0002 D.

Hyperfine Structure Constants of HF and DF

The radio frequency spectrum of HF and DF is measured by the molecular‐beam electric resonance method. The measurements are in the lowest vibrational state (υ = 0) and first rotational state (J = 1). The constants obtained are: HFDFμ (D)1.826526 (7)1.818805 (5)CF (kHz)307.637 (20)158.356 (45)CH (kHz)− 71.128 (24)− 5.755 (19)SHF (kHz)28.675 (5)4.434 (9)JHF (kHz)0.529 (23)(eqQ) D354.238 (78) The electron coupled spin–spin interaction, JHF = + 530 Hz.

Hyperfine Structure and Dipole Moment of CH3D

The electric resonance spectrum of deuteromethane (CH3D) was measured in the two rotational states, J = 1, K = 1 and J = 2, K = 2. From these data the dipole moment and hyperfine constants of the molecule were obtained. The results for the methane‐related spin rotation constants are cα = 16.54 ± 0.35, and cβ = − 1.58 ± 1.0 kHz. The quadrupole coupling constant eqQ at the deuterium nucleus is found to be eqQ = 191.48 ± 0.77 kHz. The electric dipole moments μ(J, K) are μ(1, 1) = 5.6409 × 10−3 and μ(2, 2) = 5.6794 × 10−3D.

Electric Dipole Moment of SiO and GeO

The molecular beam electric resonance spectra of SiO and GeO have been measured. The electric dipole moments (in Debye) of SiO and GeO in the lower vibrational states are: V28SiO74GeO03.09823.282413.11783.303223.13723.323933.1574 The difference between observed and calculated dipole moment is quite similar in CO and SiO.

Determination of Hyperfine Constants and Nuclear Shielding in Methyl Fluoride and Comparison with Other Molecules

The molecular‐beam electric resonance spectrum of methyl fluoride (CH3F) was measured in several rotational states. From analysis of the spectra the hyperfine structure of the molecule was determined. The hyperfine constants are (kilohertz): ζα=0.8±1.5, ζβ=14.66±0.7 for the spin—rotation interactions of the hydrogen nuclei, and cα=4.0±1.9, cβ=−51.1±1.3 for the spin—rotation at the fluorine. These results are combined with nuclear shielding data to calculate contributions to shielding and the electrostatic potential at the nucleus. Quantitative comparison is made with other molecules.

Geometry of Some Refractory Metal Dioxides

The deflection by an electrostatic quadrupole of molecular beams of SiO2, TiO2, ZrO2, CeO2, ThO2, TaO2, and UO2 has been measured. Of the above species only SiO2 was found to be nonpolar while the remaining species were found polar. This sequence (with the exception of TaO2 and UO2) together with CO2 forms an isoelectronic sequence with previously investigated alkaline‐earth difluorides. In each instance the geometry of isoelectronic partners is similar.

Polar Distortions in ReF7 and IF7

The deflection of molecular beams of ReF7 and IF7 by inhomogeneous electric fields has been studied as a function of temperature. Polar components were readily observed in molecular beams of ReF7, and their intensity increased as the temperature was lowered. A similar effect was just observable for IF7 at the lowest temperatures attainable. These observations show that the heptafluorides do not have rigid polar structures, but they are compatible with nonrigid distorted geometries for ReF7 and IF7.

Electric Deflection of Binary Hexafluorides

The deflections of molecular beams of the binary hexafluorides SF6, SeF6, TeF6, MoF6, WF6, UF6, RuF6, RhF6, ReF6, OsF6, IrF6, and PtF6 in an electric quadrupole field have been studied. In no case was refocusing of the molecular beam observed when an electric field was applied. The reduced or unchanged signals are characteristic of beams of nonpolar molecules and support the assignment of centrosymmetric structures to the hexafluorides. The OsO4 was also found to be nonpolar.