ℓ-Resonance effects in the νv5, 2ν5←ν5, and ν4 + ν5←ν4 bands of C2H2 and 13C12CH2 near 13.7 μm

Abstract An extension to the previous LSCD (lower state combination difference) determination of molecular parameters involving acetylene's ν 5 fundamental and the strongest one quantum hotbands, 2ν 5 ←ν 5 and ν 4 + ν 5 ←ν 4 [ J. Molec. Spectrosc. 146 , 389 (1991)] has been made. A novel iterative numerical diagonalization procedure was employed to fit the vibrational states involved in the seven one quantum hotbands. This method utilizes the Hellmann—Feynman theorem to calculate first derivatives and singular value decomposition (SVD) in its least-square procedure and permits the simultaneous evaluation of the effective dipole moment responsible for the l-type resonance effect upon IR intensities. A set of molecular parameters describing the rotation—vibration levels of the ground state, ν 5 , ν 4 , 2ν 5 and ν 4 + ν 5 for the major isotope and for 13 C 12 CH 2 are reported based upon FT-spectrometric data taken at the McMath Solar Telescope Observatory. The improved spectroscopic parameters retrieved from this investigation will serve as a database for modelling abundances of acetylene in various astrophysical sources.

[1]  D. Lide,et al.  Microwave and Infrared Measurements on HCN and DCN: Observations on l‐Type Resonance Doublets , 1967 .

[2]  J. Plíva.  Molecular constants for the bending modes of acetylene 12C2H2 , 1972 .

[3]  J. Watson.  Higher-order l-doubling of linear molecules , 1983 .

[4]  C. Rinsland,et al.  Identification of atmospheric C(2)H(2) lines in the 3230-3340-cm(-1) region of high resolution solar absorption spectra recorded at the National Solar Observatory. , 1985, Applied optics.

[5]  H. H. Nielsen,et al.  Rotational distortion in linear molecules arising from l-type resonance , 1958 .

[6]  J. Hietanen.  l-Responance effects in the hot bands 3v 5 ← 2v 5, (v 4 + 2v 5) ← (v 4 + v 5) and (2v 4 + v 5) ← 2v 4 of acetylene , 1983 .

[7]  T. Owen,et al.  Ethane and acetylene abundances in the Jovian atmosphere , 1976 .

[8]  S. Ridgway,et al.  High-resolution spectra of Jupiter in the 744-980 inverse centimeter spectral range , 1979 .

[9]  J. Susskind,et al.  The 12 micron band of ethane - High-resolution laboratory analysis with candidate lines for infrared heterodyne searches , 1984 .

[10]  L. Horn,et al.  Infrared Observations of the Saturnian System from Voyager 2 , 1979, Science.

[11]  Laurence S. Rothman,et al.  Determination of vibrational energy levels and parallel band intensities of 12C16O2 by Direct Numerical Diagonalization , 1986 .

[12]  J. Kauppinen,et al.  High-resolution infrared spectrum of acetylene in the region of the bending fundamental v 5 , 1981 .

[13]  J. V. Auwera,et al.  L-type resonances in C2H2 , 1991 .

[14]  G. Orton,et al.  Observational constraints on the atmospheres of Uranus and Neptune from new measurements near 10 μm , 1983 .

[15]  M. Herman,et al.  The A-X band system of acetylene: Analysis of long-wavelength bands, and vibration-rotation constants for the levels nν4 (n = 0–4), nν3 (n = 0–3), and ν2 + nν3 (n = 0–2) , 1982 .

[16]  S. Atreya,et al.  Methane photochemistry and haze production on Neptune , 1988 .

[17]  William E. Blass,et al.  An infrared study of the bending region of acetylene , 1991 .

[18]  M. Winnewisser,et al.  Millimeter wave rotational spectrum of HCNO in vibrationally excited states , 1972 .

[19]  B. Bézard,et al.  The composition of Saturn's atmosphere at northern temperate latitudes from Voyager IRIS spectra - NH3, PH3, C2H2, C2H6, CH3D, CH4, and the Saturnian D/H isotopic ratio , 1984 .

[20]  J. Watson.  Reflection symmetries of linear-molecular rovibronic levels , 1991 .

[21]  H. H. Nielsen,et al.  Vibrational l-type doubling and l-type resonance in linear polyatomic molecules , 1958 .

[22]  J. I. Musher.  Comment on Some Theorems of Quantum Chemistry , 1966 .

[23]  D. Jennings,et al.  Double passing the Kiff Peak 1-m Fourier transform spectrometer. , 1985, Applied optics.

[24]  W. Rowe,et al.  An application of the Hellmann-Feynman theorem to vibration-rotation interactions , 1975 .

[25]  Richard N. Zare,et al.  The labeling of parity doublet levels in linear molecules , 1975 .

[26]  J. Kauppinen,et al.  Vibration-rotation infrared spectra of the carbon-13 isotopic varieties of acetylene at 13·7 microns , 1986 .

[27]  S. Castellano,et al.  ANALYSIS OF NMR SPECTRA BY LEAST SQUARES , 1964 .