Jack G. Kay

Matrix-isolated FeO, NiO, and CoO: Ground-state vibrational frequencies☆

Abstract The infrared vibrational spectra of the FeO, NiO, and CoO molecules have been observed in Ar matrices at 14 K. Frequencies for each of the isotopomers 54Fe16O, 54Fe18O, 56Fe16O, 56Fe18O, 58Ni16O, 58Ni18O, 60Ni16O, 60Ni18O, 59Co16O, and 59Co18O were measured. The derived vibrational constants are: w e = 880.02 ± 1.2 and w e x e = 3.47 ± 0.6 cm −1 for 56 Fe 16 O; w e = 837.61 ± 1.1 and w e x e = 5.92 ± 0.6 cm −1 for 58 Ni 16 O; and w e = 853.75 ± 1.2 and w e x e = 3.65 ± 0.6 cm −1 for 59 Co 16 O. These results support the assignment of 5Σ+ as the ground state of FeO, 3Σ− as the ground state of NiO, and 4Σ− as the ground state of CoO.

Correlation of structure and vibrational spectra of the zwitterion L-alanine in the presence of water: an experimental and density functional analysis.

Infrared vibrational spectra were collected along with the vibrational circular dichroism (VCD) spectra for the zwitterions alpha-D-alanine, alpha-L-alanine, alpha-D-mannose and alpha-L-mannose as potassium bromide (KBr) pressed samples. VCD for D- and L-alanine dissolved in water was also measured and compared against the spectra resulting from KBr pressed samples. The experimental data were compared against the ab initio B3LYP/6-31G* optimized geometry. The zwitterion structure of alpha-L-alanine was stabilized by the addition of water molecules. Computationally, beta-L-mannose was studied and resulting expected VCD bands assigned. We present the molecular structures resulting VCD spectra and infrared vibrational spectra from experimentation as compared with the computed results.

Vibrational frequencies and structural determinations of 1,4-thioxane.

We present a detailed analysis of the structure and infrared spectra of 1,4-thioxane. The vibrational frequencies of the 1,4-thioxane molecule were analyzed using standard quantum chemical techniques. Frequencies were calculated at the MP2 and DFT levels of theory using the standard 6-31G* basis set. The structural transformation of the chemical agent bis (2-chloroethyl) sulfide (HD, mustard gas) and the related symmetry to a previously study compound(4) makes the symmetry of the 1,4-thioxane molecule an interesting candidate for study. The molecule exists normally in a Cs configuration similar to the chair form of cyclohexane. High-energy forms of 1,4-thioxane with C1 and C2 symmetry also exist.

Identification and structures of matrix-isolated ruthenium oxide molecules from infrared spectra

Abstract Matrix isolation and FTIR spectroscopy were used to study isotopically substituted ruthenium oxide molecules in argon matrices at 14 K. The species studied were produced by sputtering argon gas mixed with 16 O 2 and 18 O 2 in various proportions flowing through a hollow cathode discharge using pure ruthenium as the hollow cathode. By varying the 16 O: 18 O ratio as well as the O 2 :Ar ratio, the various isotopomers of each ruthenium oxide product could be assigned to the observed vibrational bands in the IR absorption spectra. The characteristic pattern resulting from the seven naturally occurring isotopes of Ru was particularly helpful in the identification of overlapping spectra. Metal oxides observed were RuO, RuO 2 , RuO 3 , and RuO 4 . Using isotopomer vibrational frequencies, the fundamental vibrational frequency and anharmonicity were determined for RuO and RuO 2 . In addition, the geometry of RuO 2 and RuO 3 was determined. RuO 2 is bent with a bond angle of 149 ± 2°. RuO 3 , within experimental error, appears to be trigonal planar. These are the first spectroscopic measurements reported for isolated RuO 2 and RuO 3 species.

Vibrational frequencies and structural determinations of di-vinyl sulfone

We present a detailed analysis of the structure and infrared spectra of di-vinyl sulfone. The vibrational frequencies of the di-vinyl sulfone molecule were analyzed using standard quantum chemical techniques. Frequencies were calculated at the MP2 and DFT levels of theory using the standard 6-311G* basis set. The structural transformation of the chemical agent bis(2-chloroehtyl) sulfide (HD, mustard gas) and the related symmetry to a previously study compounds [Spectrochim. Acta Part A 55 (1999) 121; Spectrochim. Acta Part A 57 (2001) 2417] makes the symmetry of the di-vinyl sulfone molecule an interesting candidate for study. The molecule exists normally in a C(2) configuration. High-energy forms of di-vinyl sulfone with C(S) and C(1) symmetries also exist.

Theoretical prediction of geometries and vibrational infrared spectra of ruthenium oxide molecules

Abstract We present computations of the optimized geometries and the corresponding vibrational frequencies of the molecules RuO2, RuO3, and RuO4. The computations utilize the Gaussian 90 Program Package, and they are based on the use of effective core potentials. In the case of RuO2, we obtain a closed shell singlet configuration with a bond angle of 150.6° and also a close and, possibly, lower lying triplet state with a bond angle of 133.7°. The trioxide is trigonal planar and the tetroxide is tetrahedral. On the whole, the calculated vibrational frequencies and geometries agree well with experimental values.

Infrared spectrum of ruthenium tetroxide isotopomers in an argon matrix

Abstract RuO4 isotopomer mixtures were synthesized with the natural abundances of Ru isotopes and mixtures of 16O and 18O. The bond-stretching region of the IR spectrum was examined using Fourier transform spectroscopy and in an argon matrix at 14 K. Wilson FG-matrix calculations permitted identification of all stretching frequencies except forbidden ν1 vibrations of Ru16O4 and Ru18O4 and confirmed undistorted tetrahedral geometry. Calculated and observed frequencies agreed with a mean deviation of 0.56 cm−1. Values compared well with gas values and with an average matrix shift of −3.2 ± 0.4 cm−1. Relative intensities were well matched using the simple classical concept of additive bond dipole moments. Intense UV irradiation of the mixture did not dissociate the RuO4 into smaller fragments, contrary to the behavior of the gas.

Absolute Determination of Radon in me Marine Troposphere

Abstract A method for the direct determination of radon in the atmosphere was developed to measure radon mixing ratio with high precision at the low levels found in the marine troposphere away from continental air mass contamination. Developed for the DYCOMS atmospheric dynamic and chemical measurement experiment over the eastern Pacific Ocean during July and August, l985 it combines scintillation cell counting with the collection of large volume air samples using low flying aircraft. An equation that combines the growth and decay of radon and radon progeny was written for a microcomputer and is used to compare alpha activity in the cell with the number of radon atoms in a sample. Radon mixing ratios as low as 12 atoms per liter of air have been measured using this method.