The electronic absorption spectrum of the CNO free radical in the gas phase

A new band with heads at 796.3.3 and 7893.1 A has been found during the flash photolysis of 3-methyl-4-oximinoisoxazol-5(411)-one. By comparison with earlier work in a neon matrix. and on the basis of a partial rotational analysis, the band is assigned as the 0 0 band of the A²x⁺-X²11_i transition of the CNO free radical. Preliminary mlecular constant are given.     

Isotope effects in the CO dimer: millimeter wave spectrum and rovibrational calculations of (12C18O)2

The millimeter wave spectrum of the isotopically substituted CO dimer, (12C18O)2, was studied with the Orotron jet spectrometer, confirming and extending a previous infrared study [A. R. W. McKellar, J. Mol. Spectrosc. 226, 190 (2004)]. A very dilute gas mixture of CO in Ne was used, which resulted in small consumption of 12C18O sample gas and produced cold and simple spectra. Using the technique of combination differences together with the data from the infrared work, six transitions in the 84-127 GHz region have been assigned. They belong to two branches, which connect four low levels of A+ symmetry to three previously unknown levels of A- symmetry. The discovery of the lowest state of A- symmetry, which corresponds to the projection K=0 of the total angular momentum J onto the intermolecular axis, identifies the geared bending mode of the 12C18O dimer at 3.607 cm(-1). Accompanying rovibrational calculations using a recently developed hybrid potential from ab initio coupled cluster [CCSD(T)] and symmetry-adapted perturbation theory calculations [G. W. M. Vissers et al., J. Chem. Phys. 122, 054306 (2005)] gave very good agreement with experiment. The isotopic dependence of the A+/A- energy splitting, the intermolecular separation R, and the energy difference of two ground state isomers, which change significantly when 18O or 13C are substituted into the normal (12C16O)2 isotopolog [L. A. Surin et al., J. Mol. Spectrosc. 223, 132 (2004)], was explained by these calculations. It turns out that the change in anisotropy of the intermolecular potential with respect to the shifted monomer centers of mass is particularly significant.     

A precise study of the rotational spectrum of formaldehyde H212C17O and H213C17O

The pure rotational spectra of H₂¹²C¹⁷O and H₂¹³C¹⁷O have been investigated in the frequency region between 8 and 360 GHz in the ground vibrational state. For both isotopic species the ¹⁷O nuclear quadrupole coupling constants and spin-rotation constants have been obtained. From both Q- and R-branch transitions a set of rotational constants and several distortion constants could be derived employing Watson's formalism in A reduction. The obtained rotational constants are in Megahertz:

     

24.

Fourier transform spectroscopy with long absortion path length in solid hydrogen: Measurement of Delta J=6 and Delta J=8 transitions     

Steinhoff RA  Winnewisser BP  Winnewisser M 《Physical review letters》1994,73(21):2833-2836

     

25.

Ground state spectroscopic constants of isothiocyanic acid,HNCS, from its microwave and millimeter wave spectra combined with far infrared data     

Koichi Yamada  Manfred Winnewisser  Gisbert Winnewisser  L.B. Szalanski  M.C.L. Gerry 《Journal of Molecular Spectroscopy》1979,78(2):189-202

The microwave and millimeter wave spectra of isothiocyanic acid, HNCS, in the ground vibrational state have been investigated in the frequency region 8–300 GHz. The a-type R-branch transitions have been assigned up to J = 25 and K_a = 4, and the a-type ^qQ₁ branch transitions up to J = 45. No b-type transitions could be identified in the frequency region covered. The far infrared data reported by Krakow, Lord, and Neely [J. Mol. Spectrosc., 27, 148 (1968)] were combined with our millimeter wave data in order to determine reliable spectroscopic constants. The rotational Hamiltonian, Watson's formalism with S reduction, has been extended empirically to higher order to facilitate the fitting of the large centrifugal distortion effects. The obtained constants are:

$\text{A = 1357.3 GHz; B = 5883.4627 MHz; C = 5845.6113 MHz; D}{}_{\mathrm{J}}\text{= 1.19393 kHz; D}{}_{\mathrm{JK}}\text{= ?1025.37 kHz; D}{}_{\mathrm{K}}\text{= 51.57 GHz; d}{}_1\text{= ?13.781 Hz; d}{}_2\text{= ?4.59 Hz.}$

The ¹⁴N quadrupole coupling constant has also been determined: χ_aa = 1.114 MHz.     

26.

Millimeter-wave spectrum of isocyanamide,H₂N-NC     

Eckhard Schäfer  Manfred Winnewisser  Jørn Johs. Christiansen 《Chemical physics letters》1981,81(2):380-386

The a-type rotational spectrum of isocyanamide was observed in the frequency range 147–300 GHz. Ether extraction of the hydrolysis products of diazomethyllithium was employed to isolate the isocyanamide. 53 rotational lines were assigned to molecules in the ground vibrational state (NH₂-inversion state 0⁺) and in the lowest excited vibrational state (NH₂-inversion state 0^?.     

27.

Millimeter wave spectrum of acetonitrile oxide,CH₃CNO,in the ν₁₀ vibrational manifold: The ground state and the state v₁₀ = 1     

M. Winnewisser  E.F. Pearson  J. Galica  B.P. Winnewisser 《Journal of Molecular Spectroscopy》1982,91(1):255-268

The pure rotational spectrum of CH₃CNO was measured in the frequency range 75 to 230 GHz. For the ground state, transitions were measured for J between 9 and 28 and for K from 0 to 12. In the v₁₀ = 1 state the measurements range from J = 0 to 19 and from K = 0 to 11. Numerous perturbations are observed, apparently due to accidental resonances with levels in other vibrational states. The contributions due to ΔK = 2, Δl = 2 matrix elements (l-type resonance and l-type doubling) are accounted for by matrix diagonalization, and the effects due to accidental resonances are presented graphically.     

28.

The Rotational Spectrum of SO(2) and the Determination of the Hyperfine Constants and Nuclear Magnetic Shielding Tensors of (33)SO(2) and SO(17)O     

Müller HS  Farhoomand J  Cohen EA  Brupbacher-Gatehouse B  Schäfer M  Bauder A  Winnewisser G 《Journal of Molecular Spectroscopy》2000,203(1):1-8

Rotational analyses of the B(2)Sigma(+)(u) --> X(2)Sigma(+)(g) system of the (14)N(+)(2) molecule have been extended to include the vibrational levels up to v' = 4. Spectral data from 20 bands obtained from high-resolution Fourier transform spectrometry of a hollow-cathode and a Pointolite lamp were included in the analysis. A global deperturbation yielded molecular parameters of the highly perturbed B(2)Sigma state and interaction parameters A(2)Pi(u) approximately B(2)Sigma(u) with a standard deviation of 0.011 cm(-1). Rotational term values of the B(2)Sigma(+) state were also determined. New perturbations in the B(2)Sigma(+) (v = 0) level have been observed at N approximately 85 and N approximately 96. Copyright 2000 Academic Press.     

29.

The Rotational Spectrum of OCCCS Revisited     

Winnewisser M  Lichau H  Wolf F 《Journal of Molecular Spectroscopy》2000,202(1):155-162

The rotational spectrum of the linear chain molecule tricarbon oxide sulfide, OCCCS, was recorded at room temperature between 118 and 179 GHz using a new commercial millimeter-wave spectrometer. The observed transitions were analyzed together with hitherto unassigned transitions from measurements between 78 and 118 GHz. About 1900 rotational transitions of OCCCS in the vibrational ground state and in 13 excited bending states could be assigned, the latter including the eighth, ninth, and tenth excited state of the low-lying bending mode nu(7) as well as the second excited state of the bending mode nu(6). Besides the determination of effective constants for these newly identified vibrational states, our data also served to considerably improve the effective constants for some of the bending states already characterized in previous publications. Copyright 2000 Academic Press.     

30.

The Fourier transform and diode laser spectrum of the ν₂ band of diazomethane     

Jürgen Vogt  Manfred Winnewisser  Koichi Yamada  Gisberg Winnewisser 《Chemical physics》1984,83(3):309-318

The infrared spectrum of the ν₂ band (NN stretching) of gaseous diazomethane at 2100 cm^?1 has been measured by means of an interferometer and a tunable diode laser spectrometer. For the first time the rotational J and K_a structure of this A-type parallel band has been resolved. Since the spectrum was found to be perturbed it was not possible to fit the upper state levels to an overall hamiltonian. Nine subbands have been analysed with the support of millimeter wave data for the ground vibrational state. Term values for the ν₂ = 1 vibrational state with K_a up to 5 have been obtained and subband origins, effective rotational constants B and centrifugal distortion constants D and H were determined for each K_a substate.     

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	H212C17O	H213C17O
$\text{A}$	281 965.0 (30)	281 987.3 (19)
$\text{B}$	37 812.287(45)	36 776.790(25)
$\text{C}$	33 214.523(31)	32 412.920(19)

Ground state spectroscopic constants of isothiocyanic acid,HNCS, from its microwave and millimeter wave spectra combined with far infrared data

The microwave and millimeter wave spectra of isothiocyanic acid, HNCS, in the ground vibrational state have been investigated in the frequency region 8–300 GHz. The a-type R-branch transitions have been assigned up to J = 25 and K_a = 4, and the a-type ^qQ₁ branch transitions up to J = 45. No b-type transitions could be identified in the frequency region covered. The far infrared data reported by Krakow, Lord, and Neely [J. Mol. Spectrosc., 27, 148 (1968)] were combined with our millimeter wave data in order to determine reliable spectroscopic constants. The rotational Hamiltonian, Watson's formalism with S reduction, has been extended empirically to higher order to facilitate the fitting of the large centrifugal distortion effects. The obtained constants are:

$\text{A = 1357.3 GHz; B = 5883.4627 MHz; C = 5845.6113 MHz; D}{}_{\mathrm{J}}\text{= 1.19393 kHz; D}{}_{\mathrm{JK}}\text{= ?1025.37 kHz; D}{}_{\mathrm{K}}\text{= 51.57 GHz; d}{}_1\text{= ?13.781 Hz; d}{}_2\text{= ?4.59 Hz.}$

The ¹⁴N quadrupole coupling constant has also been determined: χ_aa = 1.114 MHz.     

Millimeter-wave spectrum of isocyanamide,H2N-NC

The a-type rotational spectrum of isocyanamide was observed in the frequency range 147–300 GHz. Ether extraction of the hydrolysis products of diazomethyllithium was employed to isolate the isocyanamide. 53 rotational lines were assigned to molecules in the ground vibrational state (NH₂-inversion state 0⁺) and in the lowest excited vibrational state (NH₂-inversion state 0^?.     

Millimeter wave spectrum of acetonitrile oxide,CH3CNO,in the ν10 vibrational manifold: The ground state and the state v10 = 1

The pure rotational spectrum of CH₃CNO was measured in the frequency range 75 to 230 GHz. For the ground state, transitions were measured for J between 9 and 28 and for K from 0 to 12. In the v₁₀ = 1 state the measurements range from J = 0 to 19 and from K = 0 to 11. Numerous perturbations are observed, apparently due to accidental resonances with levels in other vibrational states. The contributions due to ΔK = 2, Δl = 2 matrix elements (l-type resonance and l-type doubling) are accounted for by matrix diagonalization, and the effects due to accidental resonances are presented graphically.     

The Rotational Spectrum of SO(2) and the Determination of the Hyperfine Constants and Nuclear Magnetic Shielding Tensors of (33)SO(2) and SO(17)O

Rotational analyses of the B(2)Sigma(+)(u) --> X(2)Sigma(+)(g) system of the (14)N(+)(2) molecule have been extended to include the vibrational levels up to v' = 4. Spectral data from 20 bands obtained from high-resolution Fourier transform spectrometry of a hollow-cathode and a Pointolite lamp were included in the analysis. A global deperturbation yielded molecular parameters of the highly perturbed B(2)Sigma state and interaction parameters A(2)Pi(u) approximately B(2)Sigma(u) with a standard deviation of 0.011 cm(-1). Rotational term values of the B(2)Sigma(+) state were also determined. New perturbations in the B(2)Sigma(+) (v = 0) level have been observed at N approximately 85 and N approximately 96. Copyright 2000 Academic Press.     

The Rotational Spectrum of OCCCS Revisited

The rotational spectrum of the linear chain molecule tricarbon oxide sulfide, OCCCS, was recorded at room temperature between 118 and 179 GHz using a new commercial millimeter-wave spectrometer. The observed transitions were analyzed together with hitherto unassigned transitions from measurements between 78 and 118 GHz. About 1900 rotational transitions of OCCCS in the vibrational ground state and in 13 excited bending states could be assigned, the latter including the eighth, ninth, and tenth excited state of the low-lying bending mode nu(7) as well as the second excited state of the bending mode nu(6). Besides the determination of effective constants for these newly identified vibrational states, our data also served to considerably improve the effective constants for some of the bending states already characterized in previous publications. Copyright 2000 Academic Press.     

The Fourier transform and diode laser spectrum of the ν2 band of diazomethane

The infrared spectrum of the ν₂ band (NN stretching) of gaseous diazomethane at 2100 cm^?1 has been measured by means of an interferometer and a tunable diode laser spectrometer. For the first time the rotational J and K_a structure of this A-type parallel band has been resolved. Since the spectrum was found to be perturbed it was not possible to fit the upper state levels to an overall hamiltonian. Nine subbands have been analysed with the support of millimeter wave data for the ground vibrational state. Term values for the ν₂ = 1 vibrational state with K_a up to 5 have been obtained and subband origins, effective rotational constants B and centrifugal distortion constants D and H were determined for each K_a substate.