ABSTRACT
The vibrational frequencies and corresponding normal mode assignments of the germanium monoxide tetramer (Ge4O4) in Td symmetry are examined theoretically using the Gaussian03 set of quantum chemistry codes and compared against available experimental data. All normal modes were successfully assigned to one of two types of motion predicted by a group theoretical analysis (Ge-O stretch and Ge-O-Ge bend) utilizing the Td symmetry of the molecule. The molecule possesses a cubane-like structure.
Subject(s)
Germanium/chemistry , Molecular Conformation , Spectrophotometry, Infrared , Spectrum Analysis, Raman , VibrationABSTRACT
The normal mode frequencies and corresponding vibrational assignments of dicyanodifluorosulfur are examined theoretically using the Gaussian03 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of six types of motion predicted by a group theoretical analysis (CN stretch, SC stretch, SF stretch, FSC bend, SCN bend, and CSC bend) utilizing the C(2v) symmetry of the molecule. A set of uniform scaling factors was derived for each type of motion. Predicted infrared and Raman intensities are reported.
Subject(s)
Nitriles/chemistry , Sulfur Compounds/chemistry , Sulfur/chemistry , Models, Molecular , Molecular Conformation , Thermodynamics , VibrationABSTRACT
We present a detailed analysis of the structure and infrared spectra of divinyl sulfoxide. The vibrational frequencies of the divinyl sulfoxide 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 molecule exists normally in a C(s) configuration. High-energy forms of divinyl sulfoxide with C(S) and C(1) symmetries also exist.
Subject(s)
Models, Molecular , Spectrophotometry, Infrared , Sulfoxides/chemistry , Molecular Conformation , Molecular Structure , Spectroscopy, Fourier Transform Infrared , Sulfoxides/analysisABSTRACT
Results are presented on the passive standoff detection and identification of chemical warfare (CW) liquid agents on surfaces by the Fourier-transform IR radiometry. This study was performed during surface contamination trials at Defence Research and Development Canada-Suffield in September 2002. The goal was to verify that passive long-wave IR spectrometric sensors can potentially remotely detect surfaces contaminated with CW agents. The passive sensor, the Compact Atmospheric Sounding Interferometer, was used in the trial to obtain laboratory and field measurements of CW liquid agents, HD and VX. The agents were applied to high-reflectivity surfaces of aluminum, low-reflectivity surfaces of Mylar, and several other materials including an armored personnel carrier. The field measurements were obtained at a standoff distance of 60 m from the target surfaces. Results indicate that liquid contaminant agents deposited on high-reflectivity surfaces can be detected, identified, and possibly quantified with passive sensors. For low-reflectivity surfaces the presence of the contaminants can usually be detected; however, their identification based on simple correlations with the absorption spectrum of the pure contaminant is not possible.
Subject(s)
Algorithms , Chemical Warfare Agents/analysis , Environmental Monitoring/instrumentation , Equipment Contamination/prevention & control , Interferometry/instrumentation , Spectroscopy, Fourier Transform Infrared/instrumentation , Transducers , Environmental Monitoring/methods , Interferometry/methods , Organothiophosphorus Compounds/analysis , Reproducibility of Results , Sensitivity and Specificity , Spectroscopy, Fourier Transform Infrared/methods , Surface PropertiesABSTRACT
The normal mode frequencies and corresponding vibrational assignments of trimethylarsine oxide are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of eight types of motion (As-C stretch, As=O stretch, C-H stretch, C-As-C bend, As=O bend, H-C-H bend, CH3 wag, and CH3 twist) utilizing the C3v symmetry of the molecule. Calculations were performed at the Hartree-Fock, DFT(B3LYP), and MP2 levels of theory using the standard 6-311G** basis. Calculated infrared intensities and Raman activities are reported.
Subject(s)
Arsenicals/chemistry , Vibration , Models, Molecular , Molecular Conformation , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of 1,3-dichloro-1,3-diazetidine-2,4-dione are examined theoretically using the Gaussian 98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of six types of motion predicted by a group theoretical analysis (C=O stretch, N-C stretch, N-Cl stretch, N-C-N bend, N-Cl bend, and C=O bend) utilizing the C2h symmetry of the molecule. Uniform scaling factors was derived for each type of motion. Predicted infrared and Raman intensities are reported.
Subject(s)
Azetidines/chemistry , Models, Chemical , Molecular Structure , Quantum Theory , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of diethynyldimethylsilane are examined theoretically using the Gaussian 98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of nine types of motion predicted by a group theoretical analysis (Si-C stretch, C[triple bond]C stretch, C-H stretch, C[triple bond]C-H bend, Si-C[triple bond]C bend, C-Si-C bend, H-C-H bend, CH3 wag, and CH3 twist) utilizing the C3v symmetry of the molecule. A set of uniform scaling factors was derived for each type of motion. Predicted infrared and Raman intensities are reported.
Subject(s)
Silanes/chemistry , Molecular Structure , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of triethynylmethylgermane are examined theoretically using the Gaussian98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of nine types of motion predicted by a group theoretical analysis Ge-C stretch, C[triple bond]C stretch, C-H stretch, C[triple bond]C-H bend, Ge-C[triple bond]C bend, C-Ge-C bend, H-C-H bend, CH3 wag, and CH3 twist) utilizing the C3v symmetry of the molecule. Uniform scaling factors were derived for each type of motion. Predicted infrared and Raman intensities are reported.
Subject(s)
Germanium/chemistry , Organometallic Compounds/chemistry , Molecular Structure , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The vibrational frequencies and corresponding normal mode assignments of digermylcarbodiimide are examined theoretically using the Gaussian98 set of quantum chemistry codes. All normal modes were successfully assigned to one of eight types of motion (N=C=N asymmetric stretch, N=C=N symmetric stretch, Ge-H stretch, Ge-N stretch, H-Ge-H bend, GeH(3) wag, GeH(3) twist, and Ge-N. . .N-Ge torsion) utilizing the C(2) symmetry of the molecule. Uniform scaling factors were derived for each type of motion. Predicted infrared and Raman intensities are reported.
Subject(s)
Carbodiimides/chemistry , Germanium/chemistry , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of phosphorous tricyanide (P(CN)(3)) are examined theoretically using the Gaussian98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of four types of motion predicted by a group theoretical analysis P-C stretch, CN stretch, P-C[triple bond]C bend, and C-P-C bend) utilizing the C(3v) symmetry of the molecule. A uniform scaling factor was derived for each type of motion. Predicted infrared and Raman intensities are reported.
Subject(s)
Cyanides/chemistry , Phosphorus Compounds/chemistry , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of tetrafluoroformaldazine (F(2)CNNCF(2)) are examined theoretically using the Gaussian98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of nine types of motion predicted by a group theoretical analysis (C-F stretch, C[triple bond]N stretch, N-N stretch, C=C-N bend, CF(2) wag, CF(2) rock CF(2) scissors, CF(2) twist, and C=N-N=C torsion) utilizing the C(2h) symmetry of the molecule. Uniform scaling factors was derived for each type of motion. Predicted infrared and Raman intensities are reported.
Subject(s)
Fluorine/chemistry , Organic Chemicals/chemistry , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of Al(8)S(12) in T(h) symmetry are examined theoretically using the Gaussian98 set of quantum chemistry codes. All normal modes were successfully assigned to one of four types of motion (Al-S stretch, Al-S-Al bend, S-Al-S bend, and Al-S-Al wag) predicted by a group theoretical analysis. Normal mode frequencies are predicted and calculated infrared intensities and Raman activities are presented. The thermodynamics of the reaction 2Al(4)S(6)-->Al(8)S(12) are examined.
Subject(s)
Aluminum/chemistry , Sulfur/chemistry , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of Triethynylmethylstannane (SnCH(3)(CCH)(3)) are examined theoretically using the Gaussian 98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of nine types of motion predicted by a group theoretical analysis (Sn-C stretch, C[triple bond]C stretch, C-H stretch, C[triple bond]C-H bend, Sn-C[triple bond]C bend, C-Sn-C bend, H-C-H bend, CH(3) wag, and CH(3) twist) utilizing the C(3v) symmetry of the molecule. A set of uniform scaling factors was derived for each type of motion. Predicted infrared and Raman intensities are reported.
Subject(s)
Tin Compounds/chemistry , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of digermyl ether in C(2v) symmetry are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of six types of motion (Ge-H stretch, Ge-O stretch, Ge-O-Ge bend, H-Ge-H bend, GeH(3) wag, and GeH(3) twist) predicted by a group theoretical analysis. By comparing the vibrational frequencies with IR and Raman spectra available in the literature, a set of scaling factors is derived. Predicted infrared and Raman intensities are reported.
Subject(s)
Ethers/chemistry , Germanium/chemistry , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of adamantane in Td symmetry are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of eight types of motion predicted by a group theoretical analysis. The vibrational modes of the deuterated form of adamantane were also calculated and compared against experimental data.
Subject(s)
Adamantane/chemistry , Deuterium , Molecular Structure , Quantum Theory , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of Triethynylmethylsilane (CH3Si(CCH)3) are examined theoretically using the Gaussian98 set of quantum chemistry codes. Each of the vibrational modes was assigned to one of nine types of motion predicted by a group theoretical analysis (Si-C stretch, C triple bond C stretch, C-H stretch, C triple bond C-H bend, Si-C triple bond C bend, C-Si-C bend, H-C-H bend, CH3 wag, and CH3 twist) utilizing the C3v symmetry of the molecule. A set of uniform scaling factors was derived for each type of motion. Predicted infrared and Raman intensities are reported.
Subject(s)
Silanes/chemistry , Molecular Structure , Quantum Theory , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and the corresponding vibrational assignments of tetraphosphorus decaoxide (P4O10) in tetrahedral (Td) symmetry are examined theoretically and experimentally. The Gaussian 98 set of quantum chemistry codes at the HF/6-311G*, MP2/6-311G*, and DFT/B3LYP/6-311G* levels of theory are used. By comparison to experimental normal mode frequencies deduced by Gilliam et al. [J. Phys. Chem. B 107 (2003) 2892], Chapman [Spectrochim. Acta A, 24 (1968) 1687], Beattie et al. [J. Chem. Soc. A (1970) 449], Konings et al. [J. Mol. Spectrosc. 152 (1992) 29] and the present work, correction factors for predominant vibrational motions are determined and compared. Normal modes were decomposed into five non-redundant motions (P-O stretch, P=O stretch, P-O-P bend, P-O-P wag, and P=O wag). Standard deviations found for the HF, MP2, and DFT corrected frequencies compared to experiment are 9, 5, and 4 cm(-1), respectively. Electron distribution for selected molecular orbitals is considered.
Subject(s)
Phosphorus Compounds/chemistry , Electrons , Molecular Structure , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of of tetraiododiphosphine in C2h symmetry are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of six types of motion (P-I stretch, P-P stretch, PI2 scissors, PI2 twist, PI2 wag, and PI2 rock) predicted by a group theoretical analysis. Computed vibrational frequencies are with IR and Raman spectra available in the literature, and uniform scaling factors are derived. Theoretical IR and Raman intensities are reported.
Subject(s)
Phosphines/chemistry , Iodides/chemistry , Molecular Structure , Spectrophotometry, Infrared , Spectrum Analysis, Raman , ThermodynamicsABSTRACT
The normal mode frequencies and corresponding vibrational assignments of tetrachlorobutatriene in D2h symmetry are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of the six types of motion (C=C stretch, CCl2 scissors, CCl2 twist, CCl2 wag, CCl2 rock, and C=C=C bend) predicted by a group theoretical analysis. By comparing the vibrational frequencies with IR and Raman spectra available in the literature, a set of scaling factors is derived.
Subject(s)
Chlorine/chemistry , Organic Chemicals/chemistry , Spectrophotometry, Infrared , Spectrum Analysis, RamanABSTRACT
The normal mode frequencies and corresponding vibrational assignments of trichloroboroxine (B3O3Cl3) in D3h symmetry are examined theoretically using the Gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one of five types of motion (B-Cl stretch, B-O stretch, B-Cl bend, O-B-O bend, and B(OOCl) umbrella motion) predicted by a group theoretical analysis. By comparing the vibrational frequencies with IR and Raman spectra available in the literature, a set of scaling factors is derived. Molecular orbitals and bonding are examined.