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.     

Substitution structure of cyanogen, NCCN, from high-resolution far infrared spectra

The lowest lying vibrational bands of the gas-phase spectra of cyanogen, NCCN, and four of its isotopomers, , , , and , were recorded with a Fourier transform interferometer. The resolution was limited by the maximum optical path difference (MOPD) attainable with the interferometer to . Rovibrational transitions of the ν₅ () and also the ν₂-ν₅ () band systems were assigned for all five isotopomers. The use of an effective Hamiltonian for linear molecules to fit the data yielded precise spectroscopic vibrational and rotational constants for the vibrational states (v₁v₂v₃v₄v₅) or (v₄v₅)=(00), (01), (02), (03), and (01000). These data include the first rotationally resolved transitions involving (01000). Complete substitution (r_s) structures of cyanogen, based on both single and double isotopic substitution of the parent species, were calculated. The derived structure is r_CC=138.48(17) pm and r_CN=115.66(13) pm. The two r_s structures coincide within the errors due to remaining contributions of zero-point vibrations.     

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 centrifugal distortion constants of disulfur monoxide

The microwave spectrum of the molecular transient disulfur monoxide, S₂O, has been reexamined and the microwave measurements have been extended into the millimeterwave region. From the present data, the following ground-state rotational constants and quartic distortion constants have been obtained (MHz):

$\text{A = 41915.44,}\text{B = 5059.07,}\text{C = 4507.19}$

$\text{δ}{}_{\mathrm{J}}\text{= 1.895 X 10}{}^{\mathrm{?}}\text{, δ}{}_{\mathrm{JK}}\text{= ?3.192 X 10}{}^{\mathrm{?2}}\text{,}\text{δ}{}_{\mathrm{K}}\text{= 1.197 X 10}{}^0$

$\text{δ}{}_{\mathrm{J}}\text{= 3.453 X 10}{}^{\mathrm{?4}}\text{and δ}{}_{\mathrm{K}}\text{= 1.223 X 10}{}^{\mathrm{?2}}$

The centrifugal distortion constants obtained from the rotational spectrum are used to discuss the vibrational spectrum of disulfur monoxide.